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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.2730 | Stefano Bellucci | S. Bellucci, A. Marrani, E. Orazi and A. Shcherbakov | Attractors with Vanishing Central Charge | 17 pages, LaTeX file | Phys.Lett.B655:185-195,2007 | 10.1016/j.physletb.2007.08.079 | null | hep-th | null | We consider the Attractor Equations of particular $\mathcal{N}=2$, d=4
supergravity models whose vector multiplets' scalar manifold is endowed with
homogeneous symmetric cubic special K\"{a}hler geometry, namely of the
so-called $st^{2}$ and $stu$ models. In this framework, we derive explicit
expressions for the critical moduli corresponding to non-BPS attractors with
vanishing $\mathcal{N}=2$ central charge. Such formul\ae hold for a generic
black hole charge configuration, and they are obtained without formulating any
\textit{ad hoc} simplifying assumption. We find that such attractors are
related to the 1/2-BPS ones by complex conjugation of some moduli. By uplifting
to $\mathcal{N}=8$, d=4 supergravity, we give an interpretation of such a
relation as an exchange of two of the four eigenvalues of the $\mathcal{N}=8$
central charge matrix $Z_{AB}$. We also consider non-BPS attractors with
non-vanishing $\mathcal{Z}$; for peculiar charge configurations, we derive
solutions violating the Ansatz usually formulated in literature. Finally, by
group-theoretical considerations we relate Cayley's hyperdeterminant (the
invariant of the stu model) to the invariants of the st^{2} and of the
so-called t^{3} model.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:42:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Bellucci",
"S.",
""
],
[
"Marrani",
"A.",
""
],
[
"Orazi",
"E.",
""
],
[
"Shcherbakov",
"A.",
""
]
] |
0707.2731 | Femius Koenderink | A.F. Koenderink, R. de Waele, J.C. Prangsma, A. Polman | Plasmon dispersion in metal nanoparticle chains from angle-resolved
scattering | 4 pages, 4 figures, color | Phys. Rev. B 76, 201403R (2007) | 10.1103/PhysRevB.76.201403 | null | cond-mat.other | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present angle and frequency resolved optical extinction measurements to
determine the dispersion relation of plasmon modes on Ag and Au nanoparticle
chains with pitches down to 75 nm. The large splitting between transverse and
longitudinal modes and the band curvature are inconsistent with reported
electrostatic near-field models, and confirm that far-field retarded
interactions are important, even for $\lambda/5$-sized structures. The data
imply that lower propagation losses, larger signal bandwidth and larger maximum
group velocity then expected can be achieved for wave vectors below the light
line. We conclude that for the design of optical nanocircuits coherent
far-field couplings across the entire circuit need to be considered, even at
subwavelength feature sizes.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:48:49 GMT"
},
{
"version": "v2",
"created": "Mon, 20 Aug 2012 10:25:54 GMT"
}
] | 2012-08-21T00:00:00 | [
[
"Koenderink",
"A. F.",
""
],
[
"de Waele",
"R.",
""
],
[
"Prangsma",
"J. C.",
""
],
[
"Polman",
"A.",
""
]
] |
0707.2732 | Lassalle | Michel Lassalle | An explicit formula for the characters of the symmetric group | 22 pages, LaTeX, to appear in Math. Annalen | Mathematische Annalen 340 (2008), 383-405 | null | null | math.CO math.GR math.RT | null | We give an explicit expression of the normalized characters of the symmetric
group in terms of the contents of the partition labelling the representation.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:49:01 GMT"
}
] | 2008-02-29T00:00:00 | [
[
"Lassalle",
"Michel",
""
]
] |
0707.2733 | Mark Wyatt | M. C. Wyatt, C. J. Clarke, J. S. Greaves | Origin of the Metallicity Dependence of Exoplanet Host Stars in the
Protoplanetary Disk Mass Distribution | Accepted by MNRAS | null | null | null | astro-ph | null | The probability of a star hosting a planet that is detectable in radial
velocity surveys increases Ppl(Z) oc 10^2Z, where Z is metallicity. Core
accretion models reproduce this trend, since the protoplanetary disk of a high
metallicity star has a high density of solids and so forms cores which accrete
gas before the primordial gas disk dissipates. This paper considers the origin
of the form of Ppl(Z). We introduce a simple model in which detectable planets
form when the mass of solids in the protoplanetary disk, Ms, exceeds a critical
value. In this model the form of Ppl(Z) is a direct reflection of the
distribution of protoplanetary disk masses, Mg, and the observed Ppl(Z) is
reproduced if P(Mg>Mg') oc 1/Mg'^2. We argue that a protoplanetary disk's
sub-mm dust mass is a pristine indicator of the mass available for
planet-building and find the observed sub-mm disk mass distribution is
consistent with the observed Ppl(Z) if Ms>0.5M_J is required to form detectable
planets. Any planet formation model which imposes a critical solid mass for
planet formation would reproduce the observed Ppl(Z), and core accretion models
are empirically consistent with a threshold criterion. We identify 7
protoplanetary disks which, by rigid application of this criterion, would be
expected to form detectable planets. A testable prediction is that Ppl(Z)
should flatten both for Z>0.5dex and as more distant and lower mass planets are
discovered. Further, combining this model with one in which the evolution of a
star's debris disk is also influenced by the solid mass in its protoplanetary
disk, results in the prediction that debris disks detected around stars with
planets should be more infrared luminous than those around stars without
planets in tentative agreement with recent observations.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:51:16 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Wyatt",
"M. C.",
""
],
[
"Clarke",
"C. J.",
""
],
[
"Greaves",
"J. S.",
""
]
] |
0707.2734 | Galina L. Klimchitskaya | G. L. Klimchitskaya, U. Mohideen, and V. M. Mostepanenko, | Pulsating Casimir force | 9 pages, 4 figures, to appear in J. Phys. A: Math. Theor. (Fast Track
Communication) | J. Phys. A: Math. Theor., v. 40, p.F841-F847, 2007. | 10.1088/1751-8113/40/34/F03 | null | quant-ph | null | Based on the Lifshitz theory we show that the illumination of one (Si) plate
in the three-layer systems Au--ethanol--Si, Si--ethanol--Si and
$\alpha$-Al${}_2$O${}_3$--ethanol--Si with laser pulses can change the Casimir
attraction to Casimir repulsion and vice versa. The proposed effect opens novel
opportunities in nanotechnology to actuate the periodic movement in electro-
and optomechanical micromachines based entirely on the zero-point oscillations
of the quantum vacuum without the action of mechanical springs.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:58:18 GMT"
}
] | 2007-08-20T00:00:00 | [
[
"Klimchitskaya",
"G. L.",
""
],
[
"Mohideen",
"U.",
""
],
[
"Mostepanenko",
"V. M.",
""
]
] |
0707.2735 | Anna Wolter | A. Wolter (1), V. Beckmann (2), G. Ghisellini (1), F. Tavecchio (1),
L. Maraschi (1), L. Costamante (3), A. Celotti (4), G. Ghirlanda (1) (1
INAF-OABrera; 2 INTEGRAL SDC 3 Max-Planck fuer Kernphysic 4 SISSA) | The hard synchrotron X-ray spectrum of the TeV BL Lac 1ES 1426+428 | Proceedings of "Extragalactic Jets", Girdwood, Alaska, 21-24 May,
2007; 7 pgs, 4 figure, uses asp2006.sty | null | null | null | astro-ph | null | We have observed 1ES 1426+428 with INTEGRAL detecting it up to $\sim$150 keV.
The spectrum is hard, confirming that this source is an extreme BL Lac object,
with a synchrotron component peaking, in a $\nu F_\nu$ plot, at or above 100
keV, resembling the hard states of Mkn 501 and 1ES 2344+514. All these three
sources are TeV emitters, with 1ES 1426+428 lying at a larger redshift
(z=0.129): for this source the absorption of high energy photons by the IR
cosmic background is particularly relevant. The observed hard synchrotron tail
helps the modeling of its spectral energy distribution, giving information on
the expected intrinsic shape and flux in the TeV band. This in turn constrains
the amount of the poorly known IR background.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:59:25 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Wolter",
"A.",
""
],
[
"Beckmann",
"V.",
""
],
[
"Ghisellini",
"G.",
""
],
[
"Tavecchio",
"F.",
""
],
[
"Maraschi",
"L.",
""
],
[
"Costamante",
"L.",
""
],
[
"Celotti",
"A.",
""
],
[
"Ghirlanda",
"G.",
""
]
] |
0707.2736 | Alexander I. Nesterov | Alexander I. Nesterov | Non-Hermitian Quantum Systems and Time-Optimal Quantum Evolution | null | SIGMA 5 (2009), 069, 17 pages | 10.3842/SIGMA.2009.069 | null | quant-ph | http://creativecommons.org/licenses/by-nc-sa/3.0/ | Recently, Bender et al. have considered the quantum brachistochrone problem
for the non-Hermitian $\cal PT$-symmetric quantum system and have shown that
the optimal time evolution required to transform a given initial state
$|\psi_i\rangle$ into a specific final state $|\psi_f\rangle$ can be made
arbitrarily small. Additionally, it has been shown that finding the shortest
possible time requires only the solution of the two-dimensional problem for the
quantum system governed by the effective Hamiltonian acting in the subspace
spanned by $|\psi_i\rangle$ and $|\psi_f\rangle$. In this paper, we study a
similar problem for the generic non-Hermitian Hamiltonian, focusing our
attention on the geometric aspects of the problem.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:16:18 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Jul 2009 05:24:02 GMT"
}
] | 2009-07-07T00:00:00 | [
[
"Nesterov",
"Alexander I.",
""
]
] |
0707.2737 | C. A. Terrero-Escalante | Manavendra Mahato, Leopoldo A. Pando Zayas and Cesar A.
Terrero-Escalante | Black Holes in Cascading Theories: Confinement/Deconfinement Transition
and other Thermal Properties | 34 pages, 7 figures. Version to be published by JHEP | JHEP0709:083,2007 | 10.1088/1126-6708/2007/09/083 | MCTP-07-23 | hep-th gr-qc hep-ph | null | We present numerical evidence for a transition between the Klebanov-Strassler
background and a solution describing a black hole in the class of cascading
solutions in the chirally restored phase. We also present a number of
properties of this solution, including the running of the coupling constant,
the viscosity to entropy ratio and the drag force on a quark moving in this
background.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 14:59:51 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 17:20:30 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mahato",
"Manavendra",
""
],
[
"Zayas",
"Leopoldo A. Pando",
""
],
[
"Terrero-Escalante",
"Cesar A.",
""
]
] |
0707.2738 | Patricio Gaete | Patricio Gaete and Euro Spallucci | Confinement from gluodynamics in curved space-time | 4 pages | Phys.Rev.D77:027702,2008 | 10.1103/PhysRevD.77.027702 | USM-TH-216 | hep-th | null | We determine the static potential for a heavy quark-antiquark pair from
gluodynamics in curved space-time. Our calculation is done within the framework
of the gauge-invariant, path-dependent, variables formalism. The potential
energy is the sum of a Yukawa and a linear potential, leading to the
confinement of static charges.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:04:11 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gaete",
"Patricio",
""
],
[
"Spallucci",
"Euro",
""
]
] |
0707.2739 | Jieun Jeong | Jieun Jeong | On Cycles in the Transcription Network of Saccharomyces cerevisiae | null | null | null | null | q-bio.MN q-bio.GN | null | We investigate the cycles in the transcription network of S. cerevisiae.
Unlike a similar network of E. coli, it contains many cycles. We characterize
properties of these cycles and their place in the regulatory mechanism of the
cell. Almost all cycles in the transcription network of S. cerevisiae are
contained in a single strongly connected component, which we call LSCC (L for
``largest''), except for a single cycle of two transcription factors. Among
different physiological conditions, cell cycle has the most significant
relationship with LSCC, as the set of 64 transcription interactions that are
active in all phases of the cell cycle has overlap of 27 with the interactions
of LSCC (of which there are 49). Conversely, if we remove the interactions that
are active in all phases of the cell cycle (fewer than 1% of the total), the
LSCC would have only three nodes and 5 edges, 4 of which are active only in the
stress response subnetwork. LSCC has a special place in the topology of the
network and it can be used to define a natural hierarchy in the network; in
every physiological subnetwork LSCC plays a pivotal role. Apart from those
well-defined conditions, the transcription network of S. cerevisiae is devoid
of cycles. It was observed that two conditions that were studied and that have
no cycles of their own are exogenous: diauxic shift and DNA repair, while cell
cycle, sporulation are endogenous.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 19:58:43 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Jeong",
"Jieun",
""
]
] |
0707.2740 | Matthias Hempel | Matthias Hempel and Jurgen Schaffner-Bielich | Mass, radius, and composition of the outer crust of nonaccreting cold
neutron stars | 5 pages, 2 figures, submitted to J. Phys. G, part of the proceedings
of the Nuclear Physics in Astrophysics III conference in Dresden | J.Phys.G35:014043,2008 | 10.1088/0954-3899/35/1/014043 | null | astro-ph nucl-th | null | The properties and composition of the outer crust of nonaccreting cold
neutron stars are studied by applying the model of Baym, Pethick, and
Sutherland, which was extended by including higher order corrections of the
atomic binding, screening, exchange and zero-point energy. The most recent
experimental nuclear data from the atomic mass table of Audi, Wapstra, and
Thibault from 2003 is used. Extrapolation to the drip line is utilized by
various state-of-the-art theoretical nuclear models (finite range droplet,
relativistic nuclear field and non-relativistic Skyrme Hartree-Fock
parameterizations). The different nuclear models are compared with respect to
the mass and radius of the outer crust for different neutron star
configurations and the nuclear compositions of the outer crust.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:15:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hempel",
"Matthias",
""
],
[
"Schaffner-Bielich",
"Jurgen",
""
]
] |
0707.2741 | Riccardo Biagioli | Riccardo Biagioli | Equidistribution of negative statistics and quotients of Coxeter groups
of type B and D | 18 pages, 2 figures | null | null | null | math.CO | null | We generalize some identities and q-identities previously known for the
symmetric group to Coxeter groups of type B and D. The extended results include
theorems of Foata and Sch\"utzenberger, Gessel, and Roselle on various
distributions of inversion number, major index, and descent number. In order to
show our results we provide caracterizations of the systems of minimal coset
representatives of Coxeter groups of type B and D.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:07:11 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Biagioli",
"Riccardo",
""
]
] |
0707.2742 | Vadim A. Rodin | Vadim Rodin and Amand Faessler | Description of double beta decay within continuum-QRPA | 20 pages, 1 figure, published version | Phys.Rev.C77:025502,2008 | 10.1103/PhysRevC.77.025502 | null | nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A method to calculate the nuclear double beta decay ($2\nu\beta\beta$- and
$0\nu\beta\beta$-) amplitudes within the continuum random phase approximation
(cQRPA) is formulated. Calculations of the $\beta\beta$ transition amplitudes
within the cQRPA are performed for ^{76}Ge, ^{100}Mo and ^{130}Te. A rather
simple nuclear Hamiltonian consisting of phenomenological mean field and
zero-range residual particle-hole and particle-particle interaction is used.
The calculated M^{2\nu} are almost not affected when the single-particle
continuum is taken into account. At the same time, a regular suppression of the
$0\nu\beta\beta$-amplitude is found that can be associated with additional
ground state correlations due to collective states in the continuum. It is
expected that future inclusion of the nucleon pairing in the single-particle
continuum will somewhat compensate the suppression.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:07:33 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jun 2008 14:09:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Rodin",
"Vadim",
""
],
[
"Faessler",
"Amand",
""
]
] |
0707.2743 | Manuel Angst | M. Angst, P. Khalifah, R.P. Hermann, H.J. Xiang, M.-H. Whangbo, V.
Varadarajan, J.W. Brill, B.C. Sales, and D. Mandrus | Charge Order Superstructure with Integer Iron Valence in Fe2OBO3 | 4 pages, 5 figures. Fig. 3 is available in higher resolution from the
authors. PRL in print | Phys. Rev. Lett. 99, 086403 (2007) | 10.1103/PhysRevLett.99.086403 | null | cond-mat.str-el cond-mat.mtrl-sci | null | Solution-grown single crystals of Fe2OBO3 were characterized by specific
heat, Mossbauer spectroscopy, and x-ray diffraction. A peak in the specific
heat at 340 K indicates the onset of charge order. Evidence for a doubling of
the unit cell at low temperature is presented. Combining structural refinement
of diffraction data and Mossbauer spectra, domains with diagonal charge order
are established. Bond-valence-sum analysis indicates integer valence states of
the Fe ions in the charge ordered phase, suggesting Fe2OBO3 is the clearest
example of ionic charge order so far.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:53:15 GMT"
}
] | 2007-08-23T00:00:00 | [
[
"Angst",
"M.",
""
],
[
"Khalifah",
"P.",
""
],
[
"Hermann",
"R. P.",
""
],
[
"Xiang",
"H. J.",
""
],
[
"Whangbo",
"M. -H.",
""
],
[
"Varadarajan",
"V.",
""
],
[
"Brill",
"J. W.",
""
],
[
"Sales",
"B. C.",
""
],
[
"Mandrus",
"D.",
""
]
] |
0707.2744 | Herma Cuppen | H. M. Cuppen and Eric Herbst | Simulation of the Formation and Morphology of Ice Mantles on
Interstellar Grains | 40 pages, 11 figures, 7 tables, to be published in ApJ | null | 10.1086/521014 | null | astro-ph | null | Although still poorly understood, the chemistry that occurs on the surfaces
of interstellar dust particles profoundly affects the growth of molecules in
the interstellar medium. An important set of surface reactions produces icy
mantles of many monolayers in cold and dense regions. The monolayers are
dominated by water ice, but also contain CO, CO_{2}, and occasionally methanol
as well as minor constituents. In this paper, the rate of production of
water-ice dominated mantles is calculated for different physical conditions of
interstellar clouds and for the first time images of the morphology of
interstellar ices are presented. For this purpose, the continuous-time
random-walk Monte Carlo simulation technique has been used. The visual
extinction, density, and gas and grain temperatures are varied. It is shown
that our stochastic approach can reproduce the important observation that ice
mantles only grow in the denser regions.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:47:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cuppen",
"H. M.",
""
],
[
"Herbst",
"Eric",
""
]
] |
0707.2745 | Istvan Nandori | I. Nandori | On the renormalization of the bosonized multi-flavor Schwinger model | 13 pages, 2 figures, final version, published in Physics Letters B | Phys.Lett.B662:302-308,2008 | 10.1016/j.physletb.2008.03.011 | null | hep-th | null | The phase structure of the bosonized multi-flavor Schwinger model is
investigated by means of the differential renormalization group (RG) method. In
the limit of small fermion mass the linearized RG flow is sufficient to
determine the low-energy behavior of the N-flavor model, if it has been rotated
by a suitable rotation in the internal space. For large fermion mass, the exact
RG flow has been solved numerically. The low-energy behavior of the
multi-flavor model is rather different depending on whether N=1 or N>1, where N
is the number of flavors. For N>1 the reflection symmetry always suffers
breakdown in both the weak and strong coupling regimes, in contrary to the N=1
case, where it remains unbroken in the strong coupling phase.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:23:11 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Apr 2008 12:46:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Nandori",
"I.",
""
]
] |
0707.2746 | M. B. N. Kouwenhoven | M.B.N. Kouwenhoven (1,2), A.G.A. Brown (3), S.F. Portegies Zwart (2),
L. Kaper (2) ((1) Sheffield, (2) Amsterdam, (3) Leiden) | The primordial binary population II: Recovering the binary population
for intermediate mass stars in Sco OB2 | 36 pages, 11 figures, accepted by A&A | null | 10.1051/0004-6361:20077719 | null | astro-ph | null | We characterize the binary population in the young and nearby OB association
Scorpius OB2 using available observations of visual, spectroscopic, and
astrometric binaries with intermediate-mass primaries. We take into account
observational biases by comparing the observations with simulated observations
of model associations. The available data indicate a large binary fraction (>
70% with 3sigma confidence), with a large probability that all intermediate
mass stars in Sco OB2 are part of a binary system. The binary systems have a
mass ratio distribution of the form f(q) ~ q^-0.4. Sco OB2 has a semi-major
axis distribution of the form f(log a) ~ constant (Opik's law), in the range
5-5e6 Rsun. The log-normal period distribution of Duquennoy & Mayor results in
too few spectroscopic binaries, even if the model binary fraction is 100%. Sco
OB2 is a young association with a low stellar density; its current population
is expected to be very similar to the primordial population. The fact that
practically all stars in Sco OB2 are part of a binary (or multiple) system
demonstrates that multiplicity is a fundamental factor in the star formation
process, at least for intermediate mass stars.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:43:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kouwenhoven",
"M. B. N.",
"",
"Sheffield",
"Amsterdam"
],
[
"Brown",
"A. G. A.",
"",
"Leiden"
],
[
"Zwart",
"S. F. Portegies",
"",
"Amsterdam"
],
[
"Kaper",
"L.",
"",
"Amsterdam"
]
] |
0707.2747 | Jacques Tempere | A. Maeyens, J. Tempere | Magnetohydrodynamic properties of incompressible Meissner fluids | 12 pages, 3 figures | Eur. Phys. J. B 58, 231-236 (2007). | 10.1140/epjb/e2007-00236-x | null | cond-mat.supr-con | null | We consider a superconducting material that exists in the liquid state, more
precisely, in which the Meissner-Ochsenfeld effect persists in the liquid
state. First, we investigate how the shape of such a hypothetical Meissner
liquid will adapt to accomodate for an applied external field. In particular,
we analyse the case of a droplet of Meissner fluid, and compute the elongation
of the droplet and its quadrupole frequency as a function of the applied field.
Next, the influence of an applied field on the flow of the liquid is studied
for the case of a surface wave. We derive the dispersion relation for surface
waves on an incompressible Meissner fluid. We discuss some candidate
realizations of the Meissner fluids and for the case of a superconducting
colloid discuss which regime of wave lengths would be most affected by the
Meissner effect.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:26:53 GMT"
}
] | 2008-03-06T00:00:00 | [
[
"Maeyens",
"A.",
""
],
[
"Tempere",
"J.",
""
]
] |
0707.2748 | Thomas Sotiriou | Thomas P Sotiriou, Valerio Faraoni, Stefano Liberati | Theory of gravitation theories: a no-progress report | Invited paper in the Gravity Research Foundation 2007 special issue
to be published by Int. J. Mod. Phys. D | Int.J.Mod.Phys.D17:399-423,2008 | 10.1142/S0218271808012097 | null | gr-qc astro-ph hep-th | null | Already in the 1970s there where attempts to present a set of ground rules,
sometimes referred to as a theory of gravitation theories, which theories of
gravity should satisfy in order to be considered viable in principle and,
therefore, interesting enough to deserve further investigation. From this
perspective, an alternative title of the present paper could be ``why are we
still unable to write a guide on how to propose viable alternatives to general
relativity?''. Attempting to answer this question, it is argued here that
earlier efforts to turn qualitative statements, such as the Einstein
Equivalence Principle, into quantitative ones, such as the metric postulates,
stand on rather shaky grounds -- probably contrary to popular belief -- as they
appear to depend strongly on particular representations of the theory. This
includes ambiguities in the identification of matter and gravitational fields,
dependence of frequently used definitions, such as those of the stress-energy
tensor or classical vacuum, on the choice of variables, etc. Various examples
are discussed and possible approaches to this problem are pointed out. In the
course of this study, several common misconceptions related to the various
forms of the Equivalence Principle, the use of conformal frames and equivalence
between theories are clarified.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:35:24 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Mar 2008 04:50:18 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sotiriou",
"Thomas P",
""
],
[
"Faraoni",
"Valerio",
""
],
[
"Liberati",
"Stefano",
""
]
] |
0707.2749 | Boris Kosyakov | B.P.Kosyakov | Black holes: interfacing the classical and the quantum | comment: LaTeX, 12 pages | Found.Phys.38:678-694,2008 | 10.1007/s10701-008-9227-z | null | gr-qc | null | The central idea advocated in this paper is that {forming the black hole
horizon is attended with transition from the classical regime of evolution to
the quantum one}. We justify the following criterion for discriminating between
the classical and the quantum: {spontaneous creations and annihilations of
particle-antiparticle pairs are impossible in the classical world but possible
in the quantum world}. We show that it is sufficient to {change the overall
sign of the spacetime signature in the classical picture of field propagation
for it to be treated as its associated quantum picture}. To describe a
self-gravitating object at the last stage of its classical evolution, we
propose to use the Foldy--Wouthuysen representation of the Dirac equation in
curved spacetimes, and the Gozzi classical path integral. In both approaches,
maintaining the dynamics in the classical regime is controlled by
supersymmetry.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:36:54 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kosyakov",
"B. P.",
""
]
] |
0707.2750 | Adam Sobel | Adam H. Sobel, Gilles Bellon, Julio T. Bacmeister | Multiple Equilibria in a Single-Column Model of the Tropical Atmosphere | Submitted to Geophysical Research Letters | null | 10.1029/2007GL031320 | null | physics.ao-ph | null | A single-column model run under the weak temperature gradient approximation,
a parameterization of large-scale dynamics appropriate for the tropical
atmosphere, is shown to have multiple stable equilibria. Under conditions
permitting persistent deep convection, the model has a statistically steady
state in which such convection occurs, as well as an extremely dry state in
which convection does not occur. Which state is reached depends on the initial
moisture profile.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:45:15 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Sobel",
"Adam H.",
""
],
[
"Bellon",
"Gilles",
""
],
[
"Bacmeister",
"Julio T.",
""
]
] |
0707.2751 | Vincenzo Laporta | Vincenzo Laporta | Final stare interaction enhancement effect on the near threshold p\bar p
system in B^\pm\to p\bar p \p^\pm decay | 7 pages, 11 figures | Int.J.Mod.Phys.A22:5401-5411,2007 | 10.1142/S0217751X07037949 | null | hep-ph | null | We discuss the low-mass enhancement effect in the baryon-antibaryon invariant
mass in three-body baryonic B decays using final state interactions in the
framework of Regge theory. We show that the rescattering between baryonic pair
can reproduce the observed mass spectrum.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:55:59 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 14:18:21 GMT"
}
] | 2012-06-19T00:00:00 | [
[
"Laporta",
"Vincenzo",
""
]
] |
0707.2752 | Eric M. Schlegel | E. Lenz (1) and E. M. Schlegel (2) ((1) Tom Clark High School; (2)
University of Texas at San Antonio) | A Silver Anniversary Observation of the X-ray Emitting SN1978K in NGC
1313 | accepted AJ | Astron.J.134:1821-1826,2007 | 10.1086/521983 | null | astro-ph | null | We describe the results of a 2003 Chandra ACIS-I observation of SN1978K. The
spectrum shows little flux below 0.6 keV, in contrast to the 2002 ACIS-S
observation that showed flux to 0.4 keV. Fitting the ACIS-I spectrum alone
leads to two solutions depending upon the value of the column density. A joint
fit using a dual thermal plasma model applied to the ACIS-I and a
contemporaneous XMM spectrum, which if fit alone also leads to a two-column
solution, yields a single column density fit. The fitted temperature of the
joint fit for the soft component remains constant with the errors from previous
Chandra, XMM, and ASCA data. The hard temperature recovers from its 2000-2002
decline and corresponds to an increase in the column density during that time.
The hard (2-10 keV) light curve is confirmed to be declining. The derived
number density represents a lower limit of 1e5 depending upon the adopted
filling factor of the emitting volume, leading to an estimated mass cooling
rate of 0.1-0.15 solar masses per year.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:09:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lenz",
"E.",
""
],
[
"Schlegel",
"E. M.",
""
]
] |
0707.2753 | Zoltan Racz | T. W. Burkhardt (Temple University), G. Gyorgyi, N. R. Moloney, Z.
Racz (Eotvos University) | Extreme statistics for time series: Distribution of the maximum relative
to the initial value | 29 pages, 4 figures | null | 10.1103/PhysRevE.76.041119 | null | cond-mat.stat-mech | null | The extreme statistics of time signals is studied when the maximum is
measured from the initial value. In the case of independent, identically
distributed (iid) variables, we classify the limiting distribution of the
maximum according to the properties of the parent distribution from which the
variables are drawn. Then we turn to correlated periodic Gaussian signals with
a 1/f^alpha power spectrum and study the distribution of the maximum relative
height with respect to the initial height (MRH_I). The exact MRH_I distribution
is derived for alpha=0 (iid variables), alpha=2 (random walk), alpha=4 (random
acceleration), and alpha=infinity (single sinusoidal mode). For other,
intermediate values of alpha, the distribution is determined from simulations.
We find that the MRH_I distribution is markedly different from the previously
studied distribution of the maximum height relative to the average height for
all alpha. The two main distinguishing features of the MRH_I distribution are
the much larger weight for small relative heights and the divergence at zero
height for alpha>3. We also demonstrate that the boundary conditions affect the
shape of the distribution by presenting exact results for some non-periodic
boundary conditions. Finally, we show that, for signals arising from
time-translationally invariant distributions, the density of near extreme
states is the same as the MRH_I distribution. This is used in developing a
scaling theory for the threshold singularities of the two distributions.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 15:57:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Burkhardt",
"T. W.",
"",
"Temple University"
],
[
"Gyorgyi",
"G.",
"",
"Eotvos University"
],
[
"Moloney",
"N. R.",
"",
"Eotvos University"
],
[
"Racz",
"Z.",
"",
"Eotvos University"
]
] |
0707.2754 | Harald Dorn | Harald Dorn, Thanh Hai Ngo | On the internal space dependence of the static quark-antiquark potential
in ${\cal N}=4$ SYM plasma wind | 7 pages, 3 figures, reference and comment added, | Phys.Lett.B654:41-45,2007 | 10.1016/j.physletb.2007.08.039 | HU-EP-07/26 | hep-th | null | We study the effect of the relative S^5-angle of a quark and an antiquark on
their static potential and the related screening length in a strongly coupled
moving ${\cal N}=4$ SYM plasma. The large velocity scaling law for the
screening length holds for any relative S^5-angle $\theta$. However, the
velocity independent prefactor Z strongly depends on $\theta$. For comparison
with QCD we propose to average Z over all relative orientations on S^5. This
generates a suppression factor relative to the case $\theta =0$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:04:37 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 14:21:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dorn",
"Harald",
""
],
[
"Ngo",
"Thanh Hai",
""
]
] |
0707.2755 | Sigbjorn Hervik | Sigbjorn Hervik | Ricci Nilsoliton Black Holes | 19 pages; fixed formatting problems | J.Geom.Phys.58:1253-1264,2008 | 10.1016/j.geomphys.2008.05.001 | null | hep-th gr-qc math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We follow a constructive approach and find higher-dimensional black holes
with Ricci nilsoliton horizons. The spacetimes are solutions to Einstein's
equation with a negative cosmological constant and generalises therefore,
anti-de Sitter black hole spacetimes. The approach combines a work by Lauret --
which relate so-called Ricci nilsolitons and Einstein solvmanifolds -- and an
earlier work by the author. The resulting black hole spacetimes are
asymptotically Einstein solvmanifolds and thus, are examples of solutions which
are not asymptotically Anti-de Sitter. We show that any nilpotent group in
dimension $n\leq 6$ has a corresponding Ricci nilsoliton black hole solution in
dimension (n+2). Furthermore, we show that in dimensions (n+2)>8, there exists
an infinite number of locally distinct Ricci nilsoliton black hole metrics.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:09:35 GMT"
},
{
"version": "v2",
"created": "Tue, 6 May 2008 13:41:25 GMT"
},
{
"version": "v3",
"created": "Fri, 3 Jan 2014 15:01:36 GMT"
}
] | 2014-01-06T00:00:00 | [
[
"Hervik",
"Sigbjorn",
""
]
] |
0707.2756 | Jeanne Wilson Dr. | The COBRA collaboration: T. Bloxham, A. Boston, J. Dawson, D. Dobos,
S. P. Fox, M. Freer, B. R. Fulton, C. G\"o{\ss}ling, P.F. Harrison, M.
Junker, H. Kiel, J. McGrath, B. Morgan, D. M\"unstermann, P. Nolan, S. Oehl,
Y. Ramachers, C. Reeve, D. Stewart, R. Wadsworth, J.R. Wilson and K. Zuber | First results on double beta decay modes of Cd, Te and Zn isotopes with
the COBRA experiment | 8 pages, 7 figures | Phys.Rev.C76:025501,2007 | 10.1103/PhysRevC.76.025501 | null | nucl-ex hep-ph nucl-th | null | Four 1cm^3 CdZnTe semiconductor detectors were operated in the Gran Sasso
National Laboratory to explore the feasibility of such devices for double beta
decay searches as proposed for the COBRA experiment. The research involved
background studies accompanied by measurements of energy resolution performed
at the surface. Energy resolutions sufficient to reduce the contribution of
two-neutrino double beta decay events to a negligible level for a large scale
experiment have already been achieved and further improvements are expected.
Using activity measurements of contaminants in all construction materials a
background model was developed with the help of Monte Carlo simulations and
major background sources were identified. A total exposure of 4.34 kg.days of
underground data has been accumulated allowing a search for neutrinoless double
beta decay modes of seven isotopes found in CdZnTe. Half-life limits (90% C.L.)
are presented for decays to ground and excited states. Four improved lower
limits have been obtained, including zero neutrino double electron capture
transitions of Zn64 and Te120 to the ground state, which are 1.19*10^{17} years
and 2.68*10^{15} years respectively.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:20:26 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"The COBRA collaboration",
"",
""
],
[
"Bloxham",
"T.",
""
],
[
"Boston",
"A.",
""
],
[
"Dawson",
"J.",
""
],
[
"Dobos",
"D.",
""
],
[
"Fox",
"S. P.",
""
],
[
"Freer",
"M.",
""
],
[
"Fulton",
"B. R.",
""
],
[
"Gößling",
"C.",
""
],
[
"Harrison",
"P. F.",
""
],
[
"Junker",
"M.",
""
],
[
"Kiel",
"H.",
""
],
[
"McGrath",
"J.",
""
],
[
"Morgan",
"B.",
""
],
[
"Münstermann",
"D.",
""
],
[
"Nolan",
"P.",
""
],
[
"Oehl",
"S.",
""
],
[
"Ramachers",
"Y.",
""
],
[
"Reeve",
"C.",
""
],
[
"Stewart",
"D.",
""
],
[
"Wadsworth",
"R.",
""
],
[
"Wilson",
"J. R.",
""
],
[
"Zuber",
"K.",
""
]
] |
0707.2757 | Ioannis Parissis | M. Papadimitrakis, I. R. Parissis | Singular Oscillatory Integrals on R^n | final version, 10 pages, small typos corrected, one reference added.
To appear in Math. Z | Math. Z., 266 (2010), no. 1, 169--171 | 10.1007/s00209-009-0559-y | null | math.CA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let Pd,n denote the space of all real polynomials of degree at most d on R^n.
We prove a new estimate for the logarithmic measure of the sublevel set of a
polynomial P in Pd,1. Using this estimate, we prove a sharp estimate for a
singular oscillatory integral on R^n.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:11:33 GMT"
},
{
"version": "v2",
"created": "Fri, 18 Apr 2008 08:40:20 GMT"
},
{
"version": "v3",
"created": "Thu, 14 May 2009 10:22:18 GMT"
}
] | 2013-10-08T00:00:00 | [
[
"Papadimitrakis",
"M.",
""
],
[
"Parissis",
"I. R.",
""
]
] |
0707.2758 | Michael Mazur | The BABAR Collaboration, B. Aubert, et al | Measurement of the Semileptonic Decays B --> D tau nubar and B --> D*
tau nubar | 7 pages, 1 postscript figures, submitted to EPS 2007 | null | null | BABAR-CONF-07/004, SLAC-PUB-12675 | hep-ex | null | We present preliminary measurements of branching fractions for the
semileptonic decays B --> D tau nubar and B --> D* tau nubar, which are
potentially sensitive to non--Standard Model amplitudes. The data sample
comprises 232x10^6 Upsilon(4S) --> BBbar decays collected with the BaBar
detector at the PEP-II e+e- storage ring. We obtain B(B- --> D0 tau nubar) =
(0.63 +/- 0.38 +/- 0.10 +/- 0.06)%, B(B- --> D*0 tau nubar) = (2.35 +/- 0.49
+/- 0.22 +/- 0.18)%, B(B0bar --> D+ tau nubar) = (1.03 +/- 0.35 +/- 0.14 +/-
0.10)%, and B(B0bar --> D*+ tau nubar) = (1.15 +/- 0.33 +/- 0.04 +/- 0.04)%,
where the uncertainties are statistical, systematic, and normalization,
respectively. By combining B- and B0bar results, we also obtain the branching
fractions B(B --> D tau nubar) = (0.90 +/- 0.26 +/- 0.11 +/- 0.06)% and B(B -->
D* tau nubar) = (1.81 +/- 0.33 +/- 0.11 +/- 0.06)% (quoted for the B-
lifetime), with significances of 3.5 sigma and 6.2 sigma.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:05:07 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.2759 | Rong Xiang Mr | Rong Xiang, Guohua Luo, Weizhong Qian, Qiang Zhang, Yao Wang, Fei Wei,
Qi Li, Anyuan Cao | Encapsulation, compensation, and substitution of catalyst particles
during continuous growth of carbon nanotubes | 13 pages, 4 figures, Advanced Materials, in press | null | null | null | cond-mat.mtrl-sci cond-mat.other | null | By sequential feeding of catalyst materials, it is revealed that the active
growth sites are at the bottom of the carbon nanotubes (CNTs), and that
catalyst particles are constantly encapsulated into nanotubes from the bottom.
This gives a better insight into the mechanism of CNT formation and on ways to
control the growth process. CNTs encapsulated with different materials should
enable the study of their electronic or magnetic properties, with potential
applications as building blocks for nanoelectronics and as fillers in
composites for electromagenetic shielding.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:30:18 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Xiang",
"Rong",
""
],
[
"Luo",
"Guohua",
""
],
[
"Qian",
"Weizhong",
""
],
[
"Zhang",
"Qiang",
""
],
[
"Wang",
"Yao",
""
],
[
"Wei",
"Fei",
""
],
[
"Li",
"Qi",
""
],
[
"Cao",
"Anyuan",
""
]
] |
0707.2760 | Florian Zickfeld | Paul Bonsma, Florian Zickfeld | Spanning Trees with Many Leaves in Graphs without Diamonds and Blossoms | 25 pages, 27 Figures | null | null | null | math.CO | null | It is known that graphs on n vertices with minimum degree at least 3 have
spanning trees with at least n/4+2 leaves and that this can be improved to
(n+4)/3 for cubic graphs without the diamond K_4-e as a subgraph. We generalize
the second result by proving that every graph with minimum degree at least 3,
without diamonds and certain subgraphs called blossoms, has a spanning tree
with at least (n+4)/3 leaves, and generalize this further by allowing vertices
of lower degree. We show that it is necessary to exclude blossoms in order to
obtain a bound of the form n/3+c.
We use the new bound to obtain a simple FPT algorithm, which decides in
O(m)+O^*(6.75^k) time whether a graph of size m has a spanning tree with at
least k leaves. This improves the best known time complexity for MAX LEAF
SPANNING TREE.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:26:25 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Bonsma",
"Paul",
""
],
[
"Zickfeld",
"Florian",
""
]
] |
0707.2761 | Tom Lancaster | T. Lancaster, S.J. Blundell, P.J. Baker, M.L. Brooks, W. Hayes, F.L.
Pratt, J.L. Manson, M.M. Conner, J.A. Schlueter | Muon-fluorine entangled states in molecular magnets | 4 pages, 3 figures | Phys. Rev. Lett. 99, 267601 (2007) | 10.1103/PhysRevLett.99.267601 | null | cond-mat.str-el | null | The information accessible from a muon-spin relaxation experiment is often
limited since we lack knowledge of the precise muon stopping site. We
demonstrate here the possibility of localizing a spin polarized muon in a known
stopping state in a molecular material containing fluorine. The muon-spin
precession that results from the entangled nature of the muon-spin and
surrounding nuclear spins is sensitive to the nature of the stopping site and
we use this property to identify three classes of site. We are also able to
describe the extent to which the muon distorts its surroundings.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:26:30 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lancaster",
"T.",
""
],
[
"Blundell",
"S. J.",
""
],
[
"Baker",
"P. J.",
""
],
[
"Brooks",
"M. L.",
""
],
[
"Hayes",
"W.",
""
],
[
"Pratt",
"F. L.",
""
],
[
"Manson",
"J. L.",
""
],
[
"Conner",
"M. M.",
""
],
[
"Schlueter",
"J. A.",
""
]
] |
0707.2762 | Katerina Pozdeeva | Ekaterina Pozdeeva | Darboux Transformation of the Green Function for the Dirac Equation with
the Generalized Potential | 14 pages,zip. file: Latex, 1 figure. Typos corrected, the figure
replaced | Int.J.Mod.Phys.A23:247-258,2008 | 10.1142/S0217751X08038500 | null | hep-th | null | We consider the Darboux transformation of the Green functions of the regular
boundary problem of the one-dimensional stationary Dirac equation. We obtained
the Green functions of the transformed Dirac equation with the initial regular
boundary conditions. We also construct the formula for the unabridged trace of
the difference of the transformed and the initial Green functions of the
regular boundary problem of the one-dimensional stationary Dirac equation. We
illustrate our findings by the consideration of the Darboux transformation for
the Green function of the free particle Dirac equation on an interval.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:42:29 GMT"
},
{
"version": "v2",
"created": "Sat, 21 Jul 2007 13:04:28 GMT"
},
{
"version": "v3",
"created": "Wed, 29 Aug 2007 16:32:22 GMT"
},
{
"version": "v4",
"created": "Mon, 10 Sep 2007 07:27:03 GMT"
},
{
"version": "v5",
"created": "Mon, 10 Sep 2007 21:38:45 GMT"
},
{
"version": "v6",
"created": "Wed, 19 Sep 2007 08:49:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Pozdeeva",
"Ekaterina",
""
]
] |
0707.2763 | Rong Xiang Mr | Rong Xiang, Guohua Luo, Weizhong Qian, Yao Wang, Fei Wei, Qi Li | Large Area Growth of Aligned CNT Arrays on Spheres: Towards the Large
Scale and Continuous Production | 20 pages, 12 figures, Chemical Vapor Deposition, In press | null | null | null | cond-mat.mtrl-sci cond-mat.other | null | A novel strategy for the large scale and continuous production of aligned
carbon nanotube arrays using millimeter-diameter spheres as growth substrates
is reported. The present technique is more productive than the conventional
process on flat wafers because of the higher available growth surface and the
good fluidity of the spherical substrates. It can be adapted for the industrial
production and application of aligned carbon nanotube arrays with lengths up to
millimeter.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:52:40 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Xiang",
"Rong",
""
],
[
"Luo",
"Guohua",
""
],
[
"Qian",
"Weizhong",
""
],
[
"Wang",
"Yao",
""
],
[
"Wei",
"Fei",
""
],
[
"Li",
"Qi",
""
]
] |
0707.2764 | Carlos Allende Prieto | Carlos Allende Prieto | Velocities from Cross-Correlation: A Guide for Self-Improvement | 7 pages, 3 figures, uses emulateapj.cls; to appear in the
Astronomical Journal; see http://hebe.as.utexas.edu/stools/ to obtain the
companion software | Astron.J.134:1843-1848,2007 | 10.1086/522051 | null | astro-ph | null | The measurement of Doppler velocity shifts in spectra is a ubiquitous theme
in astronomy, usually handled by computing the cross-correlation of the
signals, and finding the location of its maximum. This paper addresses the
problem of the determination of wavelength or velocity shifts among multiple
spectra of the same, or very similar, objects. We implement the classical
cross-correlation method and experiment with several simple models to determine
the location of the maximum of the cross-correlation function. We propose a new
technique, 'self-improvement', to refine the derived solutions by requiring
that the relative velocity for any given pair of spectra is consistent with all
others. By exploiting all available information, spectroscopic surveys
involving large numbers of similar objects may improve their precision
significantly. As an example, we simulate the analysis of a survey of G-type
stars with the SDSS instrumentation. Applying 'self-improvement' refines
relative radial velocities by more than 50% at low signal-to-noise ratio. The
concept is equally applicable to the problem of combining a series of
spectroscopic observations of the same object, each with a different Doppler
velocity or instrument-related offset, into a single spectrum with an enhanced
signal-to-noise ratio.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 16:59:30 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Prieto",
"Carlos Allende",
""
]
] |
0707.2765 | Stan Konings | S. Konings, C. Schuessler-Langeheine, H. Ott, E. Weschke, E. Schierle,
H. Zabel and J. B. Goedkoop | Magnetic domain fluctuations in an antiferromagnetic film observed with
coherent resonant soft x-ray scattering | to appear in Phys. Rev. Lett | null | 10.1103/PhysRevLett.106.077402 | null | cond-mat.other cond-mat.dis-nn cond-mat.mes-hall cond-mat.str-el | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We report the direct observation of slow fluctuations of helical
antiferromagnetic domains in an ultra-thin holmium film using coherent resonant
magnetic x-ray scattering. We observe a gradual increase of the fluctuations in
the speckle pattern with increasing temperature, while at the same time a
static contribution to the speckle pattern remains. This finding indicates that
domain-wall fluctuations occur over a large range of time scales. We ascribe
this non-ergodic behavior to the strong dependence of the fluctuation rate on
the local thickness of the film.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:11:16 GMT"
},
{
"version": "v2",
"created": "Sun, 25 May 2008 20:59:30 GMT"
},
{
"version": "v3",
"created": "Wed, 26 Jan 2011 14:53:44 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Konings",
"S.",
""
],
[
"Schuessler-Langeheine",
"C.",
""
],
[
"Ott",
"H.",
""
],
[
"Weschke",
"E.",
""
],
[
"Schierle",
"E.",
""
],
[
"Zabel",
"H.",
""
],
[
"Goedkoop",
"J. B.",
""
]
] |
0707.2766 | Debashish Chowdhury | Ashok Garai, Debashish Chowdhury and M. D. Betterton | A two-state model for helicase translocation and unwinding of nucleic
acids | minor modifications | Physical Review E, vol. 77, 061910 (2008). | 10.1103/PhysRevE.77.061910 | null | physics.bio-ph | null | Helicases are molecular motors that unwind double-stranded nucleic acids
(dsNA), such as DNA and RNA). Typically a helicase translocates along one of
the NA single strands while unwinding and uses adenosine triphosphate (ATP)
hydrolysis as an energy source. Here we model of a helicase motor that can
switch between two states, which could represent two different points in the
ATP hydrolysis cycle. Our model is an extension of the earlier
Betterton-J\"ulicher model of helicases to incorporate switching between two
states. The main predictions of the model are the speed of unwinding of the
dsNA and fluctuations around the average unwinding velocity. Motivated by a
recent claim that the NS3 helicase of Hepatitis C virus follows a flashing
ratchet mechanism, we have compared the experimental results for the NS3
helicase with a special limit of our model which corresponds to the flashing
ratchet scenario. Our model accounts for one key feature of the experimental
data on NS3 helicase. However, contradictory observations in experiments
carried out under different conditions limit the ability to compare the model
to experiments.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:14:47 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Sep 2007 15:23:13 GMT"
},
{
"version": "v3",
"created": "Tue, 9 Oct 2007 08:51:10 GMT"
},
{
"version": "v4",
"created": "Mon, 21 Apr 2008 15:36:30 GMT"
}
] | 2008-06-15T00:00:00 | [
[
"Garai",
"Ashok",
""
],
[
"Chowdhury",
"Debashish",
""
],
[
"Betterton",
"M. D.",
""
]
] |
0707.2767 | Cheoun Myung Ki | K. S. Kim, Myung Ki Cheoun | Strange quark contributions to neutrino and antineutrino nucleus
scattering via neutral current in quasi-elastic region | null | null | null | null | nucl-th | null | Strange quark contributions to the neutral current reaction in the neutrino
scattering are investigated on the nucleon level and extended to the $^{12}$C
target nucleus through the neutrino-induced knocked-out nucleon process in the
quasi-elastic region within the framework of a relativistic single particle
model. The incident energy range between 500 MeV and 1.0 GeV is used for the
neutrino(antineutrino) scattering. Effects of the final state interaction for
the knocked-out nucleon are included by a relativistic optical potential. We
found that the sensitivity of the strange quark contents could be salient on
the asymmetry between neutrino and antineutrino scattering cross sections. In
specific, $A (\nu ({\bar \nu}), \nu^{'} ({\bar \nu}^{'}) N)$ reaction is shown
to be very sensitive test in the searches of the strangeness.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:16:29 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 05:25:45 GMT"
},
{
"version": "v3",
"created": "Tue, 23 Oct 2007 02:10:50 GMT"
}
] | 2007-10-23T00:00:00 | [
[
"Kim",
"K. S.",
""
],
[
"Cheoun",
"Myung Ki",
""
]
] |
0707.2768 | Fabrizio Canfora | Fabrizio Canfora | Incompressible fluid inside an astrophysical black hole? | 30 pages, 2 figures. Accepted for publication on Physical Review D:
references added, typos corrected, test polished | Phys.Rev.D76:084012,2007 | 10.1103/PhysRevD.76.084012 | null | gr-qc astro-ph cond-mat.mes-hall hep-th | null | It is argued that under natural hypothesis the Fermions inside a black hole
formed after the collapse of a neutron star could form a non compressible fluid
(well before reaching the Planck scale) leading to some features of integer
Quantum Hall Effect. The relations with black hole entropy are analyzed.
Insights coming from Quantum Hall Effect are used to analyze the coupling with
Einstein equations. Connections with some cosmological scenarios and with
higher dimensional Quantum Hall Effect are shortly pointed out.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:21:18 GMT"
},
{
"version": "v2",
"created": "Wed, 29 Aug 2007 18:53:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Canfora",
"Fabrizio",
""
]
] |
0707.2769 | Helen Kirk | Helen Kirk, Doug Johnstone, Mario Tafalla | Dynamics of Dense Cores in the Perseus Molecular Cloud | 49 pages, 20 figures. Accepted for publication in the Astrophysical
Journal | null | 10.1086/521395 | null | astro-ph | null | We survey the kinematics of over one hundred and fifty candidate (and
potentially star-forming) dense cores in the Perseus molecular cloud with
pointed N2H+(1-0) and simultaneous C18O(2-1) observations. Our detection rate
of N2H+ is 62%, rising to 84% for JCMT SCUBA-selected targets. In agreement
with previous observations, we find that the dense N2H+ targets tend to display
nearly thermal linewidths, particularly those which appear to be starless
(using Spitzer data), indicating turbulent support on the small scales of
molecular clouds is minimal. For those N2H+ targets which have an associated
SCUBA dense core, we find their internal motions are more than sufficient to
provide support against the gravitational force on the cores. Comparison of the
N2H+ integrated intensity and SCUBA flux reveals fractional N2H+ abundances
between 10^-10 and 10^-9. We demonstrate that the relative motion of the dense
N2H+ gas and the surrounding C18O gas is less than the sound speed in the vast
majority of cases (~90%). The point-to-point motions we observe within larger
extinction regions appear to be insufficient to provide support against
gravity, although we sparsely sample these regions.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:24:12 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kirk",
"Helen",
""
],
[
"Johnstone",
"Doug",
""
],
[
"Tafalla",
"Mario",
""
]
] |
0707.2770 | Richard Ignace | R Ignace, J P Cassinelli, G Tracy, E B Churchwell, H J G L M Lamers | Neon Abundances from a Spitzer/IRS Survey of Wolf-Rayet Stars | to appear in Astrophysical Journal | Astrophys.J.669:600-605,2007 | 10.1086/521718 | null | astro-ph | null | We report on neon abundances derived from {\it Spitzer} high resolution
spectral data of eight Wolf-Rayet (WR) stars using the forbidden line of
[\ion{Ne}{3}] 15.56 microns. Our targets include four WN stars of subtypes
4--7, and four WC stars of subtypes 4--7. We derive ion fraction abundances
$\gamma$ of Ne^{2+} for the winds of each star. The ion fraction abundance is a
product of the ionization fraction $Q_{\rm i}$ in stage i and the abundance by
number ${\cal A}_E$ of element E relative to all nuclei. Values generally
consistent with solar are obtained for the WN stars, and values in excess of
solar are obtained for the WC stars.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:35:33 GMT"
}
] | 2009-02-16T00:00:00 | [
[
"Ignace",
"R",
""
],
[
"Cassinelli",
"J P",
""
],
[
"Tracy",
"G",
""
],
[
"Churchwell",
"E B",
""
],
[
"Lamers",
"H J G L M",
""
]
] |
0707.2771 | Sergiy Silich | Sergiy Silich, Guillermo Tenorio-Tagle and Casiana Munoz-Tunon | The pressure confined wind of the massive and compact superstar cluster
M82-A1 | 19 pages, 4 figures, accepted for publication in ApJ | null | 10.1086/521706 | null | astro-ph | null | The observed parameters of the young superstar cluster M82-A1 and its
associated compact HII region are here shown to indicate a low heating
efficiency or immediate loss, through radiative cooling, of a large fraction of
the energy inserted by stellar winds and supernovae during the early evolution
of the cluster. This implies a bimodal hydrodynamic solution which leads to a
reduced mass deposition rate into the ISM, with a much reduced outflow
velocity. Furthermore, to match the observed parameters of the HII region
associated to M82-A1, the resultant star cluster wind is here shown to ought to
be confined by a high pressure interstellar medium. The cluster wind
parameters, as well as the location of the reverse shock, its cooling length
and the radius of the standing outer HII region are derived analytically. All
of these properties are then confirmed with a semi-analytical integration of
the flow equations, which provides us also with the run of the hydrodynamic
variables as a function of radius. The impact of the results is discussed and
extended to other massive and young superstar clusters surrounded by a compact
HII region.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:37:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Silich",
"Sergiy",
""
],
[
"Tenorio-Tagle",
"Guillermo",
""
],
[
"Munoz-Tunon",
"Casiana",
""
]
] |
0707.2772 | Lorenzo Campos Venuti | Paolo Zanardi, Lorenzo Campos Venuti, Paolo Giorda | Bures metric over thermal state manifolds and quantum criticality | 9 pages, 4 figures, LaTeX problems fixed, references added | Phys. Rev. A 76, 062318 (2007) | 10.1103/PhysRevA.76.062318 | null | quant-ph | null | We analyze the Bures metric over the manifold of thermal density matrices for
systems featuring a zero temperature quantum phase transition. We show that the
quantum critical region can be characterized in terms of the temperature
scaling behavior of the metric tensor itself. Furthermore, the analysis of the
metric tensor when both temperature and an external field are varied, allows to
complement the understanding of the phase diagram including cross-over regions
which are not characterized by any singular behavior. These results provide a
further extension of the scope of the metric approach to quantum criticality.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:43:24 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jul 2007 14:33:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zanardi",
"Paolo",
""
],
[
"Venuti",
"Lorenzo Campos",
""
],
[
"Giorda",
"Paolo",
""
]
] |
0707.2773 | Fran\c{c}oise Masnou-Seeuws | Eliane Luc-Koenig, Fran\c{c}oise Masnou-Seeuws and Ronnie Kosloff | The dynamical hole in ultrafast photoassociation: analysis of the
compression effect | 31 pages, 11 figures | null | 10.1103/PhysRevA.76.053415 | null | quant-ph | null | Photoassociation of a pair of cooled atoms by excitation with a short chirped
laser pulse creates a dynamical hole in the initial continuum wavefunction.
This hole is manifested by a void in the pair wavefunction and a momentum kick.
Photoassociation into loosely bound levels of the external well in Cs_2
0$_g^-$(6S + 6P$_{3/2}$ is considered as a case study. After the pulse, the
free evolution of the ground triplet state wavepacket is analyzed. Due to a
negative momentum kick, motion to small distances is manifested and a
compression effect is pointed out, markedly increasing the density of atom
pairs at short distance. A consequence of the hole is the redistribution of the
vibrational population in the ground triplet state, with population of the last
bound level and creation of pairs of hot atoms. The physical interpretation
makes use of the time dependence of the probability current and population on
each channel to understand the role of the parameters of the photoassociation
pulse. By varying such parameters, optimization of the compression effect in
the ground state wavepacket is demonstrated. Due to an increase of the short
range density probability by more than two orders of magnitude, we predict
important photoassociation rates into deeply bound levels of the excited state
by a second pulse, red-detuned relative to the first one and conveniently
delayed.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:49:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Luc-Koenig",
"Eliane",
""
],
[
"Masnou-Seeuws",
"Françoise",
""
],
[
"Kosloff",
"Ronnie",
""
]
] |
0707.2774 | Erkan Tuzel | Erkan Tuzel, Guoai Pan, Thomas Ihle and Daniel M. Kroll | Mesoscopic model for the fluctuating hydrodynamics of binary and ternary
mixtures | 7 pages including 6 figures | null | 10.1209/0295-5075/80/40010 | null | cond-mat.soft cond-mat.stat-mech | null | A recently introduced particle-based model for fluid dynamics with continuous
velocities is generalized to model immiscible binary mixtures. Excluded volume
interactions between the two components are modeled by stochastic multiparticle
collisions which depend on the local velocities and densities. Momentum and
energy are conserved locally, and entropically driven phase separation occurs
for high collision rates. An explicit expression for the equation of state is
derived, and the concentration dependence of the bulk free energy is shown to
be the same as that of the Widom-Rowlinson model. Analytic results for the
phase diagram are in excellent agreement with simulation data. Results for the
line tension obtained from the analysis of the capillary wave spectrum of a
droplet agree with measurements based on the Laplace's equation. The
introduction of "amphiphilic" dimers makes it possible to model the phase
behavior and dynamics of ternary surfactant mixtures.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:49:55 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Tuzel",
"Erkan",
""
],
[
"Pan",
"Guoai",
""
],
[
"Ihle",
"Thomas",
""
],
[
"Kroll",
"Daniel M.",
""
]
] |
0707.2775 | Stefan Hollands | Stefan Hollands and Stoytcho Yazadjiev | Uniqueness theorem for 5-dimensional black holes with two axial Killing
fields | Latex, 21pp, no figures. v2: technical assumption added, extended
discussion of orbit space, results unchanged but sharpened | Commun.Math.Phys.283:749-768,2008 | 10.1007/s00220-008-0516-3 | null | gr-qc | null | We show that two stationary, asymptotically flat vacuum black holes in 5
dimensions with two commuting axial symmetries are identical if and only if
their masses, angular momenta, and their ``rod structures'' coincide. We also
show that the horizon must be topologically either a 3-sphere, a ring, or a
Lens-space. Our argument is a generalization of constructions of Morisawa and
Ida (based in turn on key work of Maison) who considered the spherical case,
combined with basic arguments concerning the nature of the factor manifold of
symmetry orbits.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 17:55:29 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Sep 2007 09:07:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hollands",
"Stefan",
""
],
[
"Yazadjiev",
"Stoytcho",
""
]
] |
0707.2776 | B{\l}a\.zej Szepietowski | B{\l}a\.zej Szepietowski | A presentation for the mapping class group of a non-orientable surface
from the action on the complex of curves | 45 pages, accepted for publication in Osaka J. Math | Osaka J. Math. 45 (2008), 283-326 | null | null | math.GT | null | We study the action of the mapping class group M(F) on the complex of curves
of a non-orientable surface F. We obtain, by using a result of K. S. Brown, a
presentation for M(F) defined in terms of the mapping class groups of the
complementary surfaces of collections of curves, provided that F is not
sporadic, i.e. the complex of curves of F is simply connected. We also compute
a finite presentation for the mapping class group of each sporadic surface.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:18:09 GMT"
}
] | 2016-03-28T00:00:00 | [
[
"Szepietowski",
"Błażej",
""
]
] |
0707.2777 | Christoph Bihler | C. Bihler, M. Kraus, M. S. Brandt, S.T.B. Goennenwein, M. Opel, M. A.
Scarpulla, R. Farshchi, and O. D. Dubon | Suppression of hole-mediated ferromagnetism in GaMnP by hydrogen | null | J. Appl. Phys. 104, 013908 (2008) | 10.1063/1.2952045 | null | cond-mat.mtrl-sci | null | We report the successful passivation of the Mn acceptors in GaMnP upon
exposure to a remote dc hydrogen plasma. The as-grown films are non-metallic
and ferromagnetic with a Curie temperature of T_C=55K. After hydrogenation the
sample resistivity increases by approximately three orders of magnitude at room
temperature and six orders of magnitude at 25 K. Furthermore, the hydrogenated
samples are paramagnetic, which is evidenced by a magnetization curve at 5 K
that is best described by a Brillouin function with g=2 and J=5/2 expected for
Mn atoms in the 3d^5 configuration. These observations unambiguously proof that
the ferromagnetism is carrier-mediated also in GaMnP.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:19:46 GMT"
}
] | 2008-07-10T00:00:00 | [
[
"Bihler",
"C.",
""
],
[
"Kraus",
"M.",
""
],
[
"Brandt",
"M. S.",
""
],
[
"Goennenwein",
"S. T. B.",
""
],
[
"Opel",
"M.",
""
],
[
"Scarpulla",
"M. A.",
""
],
[
"Farshchi",
"R.",
""
],
[
"Dubon",
"O. D.",
""
]
] |
0707.2778 | Drake Deming | Drake Deming, Joseph Harrington, Gregory Laughlin, Sara Seager, Sarah
B. Navarro, William C. Bowman, and Karen Horning | Spitzer Transit and Secondary Eclipse Photometry of GJ 436b | 15 pages, 2 figures, submitted to ApJ Letters | null | 10.1086/522496 | null | astro-ph | null | We report the results of infrared (8 micron) transit and secondary eclipse
photometry of the hot Neptune exoplanet, GJ436b using Spitzer. The nearly
photon-limited precision of these data allow us to measure an improved radius
for the planet, and to detect the secondary eclipse. The transit (centered at
HJD = 2454280.78149 +/-0.00016) shows the flat-bottomed shape typical of
infrared transits, and it precisely defines the planet-to-star radius ratio
(0.0839 +/-0.0005), independent of the stellar properties. However, we obtain
the planetary radius, as well as the stellar mass and radius, by fitting to the
transit curve simultaneously with an empirical mass-radius relation for
M-dwarfs (M=R). We find Rs=Ms=0.47 +/-0.02 in solar units, and Rp=27,600
+/-1170 km (4.33 +/-0.18 Earth radii). This radius significantly exceeds the
radius of a naked ocean planet, and requires a gasesous hydrogen-helium
envelope. The secondary eclipse occurs at phase 0.587 +/-0.005, proving a
significant orbital eccentricity (e=0.15 +/-0.012). The amplitude of the
eclipse (5.7 +/-0.8e-4) indicates a brightness temperature for the planet of
T=712 +/-36K. If this is indicative of the planet's physical temperature, it
suggests the occurrence of tidal heating in the planet. An uncharacterized
second planet likely provides ongoing gravitational perturbations, to maintain
GJ436b's orbit eccentricity over long time scales.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:51:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Deming",
"Drake",
""
],
[
"Harrington",
"Joseph",
""
],
[
"Laughlin",
"Gregory",
""
],
[
"Seager",
"Sara",
""
],
[
"Navarro",
"Sarah B.",
""
],
[
"Bowman",
"William C.",
""
],
[
"Horning",
"Karen",
""
]
] |
0707.2779 | Man-Hong Yung | Man-Hong Yung | Independent Noise Approximation for Spin-Boson Decoherence | 4 pages | null | null | null | quant-ph | null | Quantum error correction is a solution to preserve the fidelity of quantum
information encoded in physical systems subject to noise. However, unfavorable
correlated errors could be induced even for non-interacting qubits through the
environment (bath), when they are "packed" together. The question is, to what
extent can we treat the noise induced by the bath as independent? In the
context of the spin-boson model, we show that, under some reasonable
constraints, the independent noise approximation could be valid. On the other
hand, in the strongly correlated limit, we show how the method of decoherence
free subspace can be made applicable. Combining these two methods makes
fault-tolerant quantum computation promising in fighting against correlated
errors.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:38:50 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Yung",
"Man-Hong",
""
]
] |
0707.2780 | Aydin Sezgin | Aydin Sezgin, Mohamad Charafeddine, Arogyaswami Paulraj | On the ergodic sum-rate performance of CDD in multi-user systems | to appear in Proceedings of 2007 IEEE Information Theory Workshop
(ITW) in Lake Tahoe | null | 10.1109/ITW.2007.4313052 | null | cs.IT math.IT | null | The main focus of space-time coding design and analysis for MIMO systems has
been so far focused on single-user systems. For single-user systems, transmit
diversity schemes suffer a loss in spectral efficiency if the receiver is
equipped with more than one antenna, making them unsuitable for high rate
transmission. One such transmit diversity scheme is the cyclic delay diversity
code (CDD). The advantage of CDD over other diversity schemes such as
orthogonal space-time block codes (OSTBC) is that a code rate of one and delay
optimality are achieved independent of the number of transmit antennas. In this
work we analyze the ergodic rate of a multi-user multiple access channel (MAC)
with each user applying such a cyclic delay diversity (CDD) code. We derive
closed form expressions for the ergodic sum-rate of multi-user CDD and compare
it with the sum-capacity. We study the ergodic rate region and show that in
contrast to what is conventionally known regarding the single-user case,
transmit diversity schemes are viable candidates for high rate transmission in
multi-user systems. Finally, our theoretical findings are illustrated by
numerical simulation results.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:39:23 GMT"
}
] | 2016-11-17T00:00:00 | [
[
"Sezgin",
"Aydin",
""
],
[
"Charafeddine",
"Mohamad",
""
],
[
"Paulraj",
"Arogyaswami",
""
]
] |
0707.2781 | Bruce E. Sagan | Adam Goyt (Minnesota State U.) and Bruce Sagan (Michigan State U.) | Set partition statistics and q-Fibonacci numbers | 18 pages, see related papers at http://www.math.msu.edu/~sagan | null | null | null | math.CO | null | We consider the set partition statistics ls and rb introduced by Wachs and
White and investigate their distribution over set partitions avoiding certain
patterns. In particular, we consider those set partitions avoiding the pattern
13/2, $\Pi_n(13/2)$, and those avoiding both 13/2 and 123, $\Pi_n(13/2,123)$.
We show that the distribution over $\Pi_n(13/2)$ enumerates certain integer
partitions, and the distribution over $\Pi_n(13/2,123)$ gives q-Fibonacci
numbers. These q-Fibonacci numbers are closely related to q-Fibonacci numbers
studied by Carlitz and by Cigler. We provide combinatorial proofs that these
q-Fibonacci numbers satisfy q-analogues of many Fibonacci identities. Finally,
we indicate how p,q-Fibonacci numbers arising from the bistatistic (ls, rb)
give rise to p,q-analogues of identities.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:40:48 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jan 2008 20:50:11 GMT"
}
] | 2008-01-15T00:00:00 | [
[
"Goyt",
"Adam",
"",
"Minnesota State U."
],
[
"Sagan",
"Bruce",
"",
"Michigan State U."
]
] |
0707.2782 | Bradford Holden | B. P. Holden, G. D. Illingworth, M. Franx, J. P. Blakeslee, M.
Postman, D. D. Kelson, A. van der Wel, R. Demarco, D. K. Magee, K.-V. Tran,
A. Zirm, H. Ford, P. Rosati, N. Homeier | Mass-Selection and the Evolution of the Morphology-Density Relation from
z=0.8 to z=0 | 18 pages in emulate ApJ format, with 10 color figures, Accepted to
ApJ. Version updated to reflect published version, includes new references
and a correction to table 3 | Nov. 20, 2007, ApJ, 670, 190 | 10.1086/521777 | null | astro-ph | null | We examined the morphology-density relations for galaxy samples selected by
luminosity and by mass in each of five massive X-ray clusters from z=0.023 to
0.83 for 674 spectroscopically-confirmed members. Rest-frame optical colors and
visual morphologies were obtained primarily from Hubble Space Telescope images.
Morphology-density relations (MDR) are derived in each cluster from a complete,
luminosity-selected sample of 452 galaxies with a magnitude limit M_V <
M^{*}_{V} + 1. The change in the early-type fraction with redshift matches
previous work for massive clusters of galaxies. We performed a similar
analysis, deriving MDRs for complete, mass-selected samples of 441 galaxies
with a mass-limit of 10^{10.6} M_{\sun}. Our mass limit includes faint objects,
the equivalent of =~1 mag below L^{*} for the red cluster galaxies, and
encompasses =~70% of the stellar mass in cluster galaxies. The MDRs in the
mass-selected sample at densities of Sigma > 50 galaxies Mpc^{-2} are similar
to those in the luminosity-selected sample but show larger early-type
fractions. However, the trend with redshift in the fraction of elliptical and
S0 galaxies with masses > 10^{10.6} M_{\sun} differs significantly between the
mass- and luminosity-selected samples. The clear trend seen in the early-type
fraction from z=0 to z=~ 0.8 is not found in mass-selected samples. The
early-type galaxy fraction changes much less, and is consistent with being
constant at 92% +/- 4% at \Sigma> 500 galaxies Mpc^{-2} and 83 +/- 3% at 50 <
\Sigma < 500 galaxies Mpc^{-2}. This suggests that galaxies of mass lower than
> 10^{10.6} M_{\sun} play a significant role in the evolution of the early-type
fraction in luminosity-selected samples. (Abstract abridged)
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 19:41:10 GMT"
},
{
"version": "v2",
"created": "Mon, 29 Oct 2007 17:34:40 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Holden",
"B. P.",
""
],
[
"Illingworth",
"G. D.",
""
],
[
"Franx",
"M.",
""
],
[
"Blakeslee",
"J. P.",
""
],
[
"Postman",
"M.",
""
],
[
"Kelson",
"D. D.",
""
],
[
"van der Wel",
"A.",
""
],
[
"Demarco",
"R.",
""
],
[
"Magee",
"D. K.",
""
],
[
"Tran",
"K. -V.",
""
],
[
"Zirm",
"A.",
""
],
[
"Ford",
"H.",
""
],
[
"Rosati",
"P.",
""
],
[
"Homeier",
"N.",
""
]
] |
0707.2783 | Russell M. Kulsrud | Russell M. Kulsrud and Ellen G. Zweibel | On the Origin of Cosmic Magnetic Fields | 90 pages and 6 figures; accepted for publication in Reports of
Progress in Physics as an invited review | null | 10.1088/0034-4885/71/4/046901 | null | astro-ph | null | We review the literature concerning how the cosmic magnetic fields pervading
nearly all galaxies actually got started. some observational evidence involves
the chemical abundance of the light elements Be and B, while another one is
based on strong magnetic fields seen in high red shift galaxies. Seed fields,
whose strength is of order 10^{-20} gauss, easily sprung up in the era
preceding galaxy formation. Several mechanisms are proposed to amplify these
seed fields to microgauss strengths. The standard mechanism is the Alpha-Omega
dynamo theory. It has a major difficulty that makes unlikely to provide the
sole origin. The difficulty is rooted in the fact that the total flux is
constant. This implies that flux must be removed from the galactic discs. This
requires that the field and flux be separated, for otherwise interstellar mass
must be removed from the deep galactic gravitational and then their strength
increased by the alpha omega theory.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 19:42:13 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Mar 2008 19:49:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kulsrud",
"Russell M.",
""
],
[
"Zweibel",
"Ellen G.",
""
]
] |
0707.2784 | Eugene Kanzieper | Alexei Borodin, Eugene Kanzieper | A Note on the Pfaffian Integration Theorem | 8 pages; published version | J. Phys. A: Math. Theor. 40 (2007) F849-F855 | 10.1088/1751-8113/40/36/F01 | null | math-ph cond-mat.dis-nn hep-th math.MP math.PR nlin.SI | null | Two alternative, fairly compact proofs are presented of the Pfaffian
integration theorem that is surfaced in the recent studies of spectral
properties of Ginibre's Orthogonal Ensemble. The first proof is based on a
concept of the Fredholm Pfaffian; the second proof is purely linear-algebraic.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:51:59 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 05:32:52 GMT"
}
] | 2007-08-22T00:00:00 | [
[
"Borodin",
"Alexei",
""
],
[
"Kanzieper",
"Eugene",
""
]
] |
0707.2785 | Federico Foieri | F. Foieri, L. Arrachea, M. J. Sanchez | Multifloquet to single electronic channel transition in the transport
properties of a resistive 1D driven disordered ring | 5 pages, 4 figures | null | 10.1103/PhysRevLett.99.266601 | null | cond-mat.mes-hall | null | We investigate the dc response of a 1D disordered ring coupled to a reservoir
and driven by a magnetic flux with a linear dependence on time. We identify two
regimes: (i) A localized or large length L regime, characterized by a dc
conductance, g_{dc}, whose probability distribution P(g_{dc}) is identical to
the one exhibited by a 1D wire of the same length L and disorder strength
placed in a Landauer setup. (ii) A "multifloquet" regime for small L and weak
coupling to the reservoir, which exhibits large currents and conductances that
can be g_{dc} > 1, in spite of the fact that the ring contains a single
electronic transmission channel. The crossover length between the multifloquet
to the single channel transport regime, L_c, is controlled by the coupling to
the reservoir.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 18:54:26 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Foieri",
"F.",
""
],
[
"Arrachea",
"L.",
""
],
[
"Sanchez",
"M. J.",
""
]
] |
0707.2786 | Joao M. Baptista | J. M. Baptista | Twisting gauged non-linear sigma-models | 33 pages; v2: small additions, published version | JHEP 0802:096,2008 | 10.1088/1126-6708/2008/02/096 | ITFA-2007-31 | hep-th math.DG | null | We consider gauged sigma-models from a Riemann surface into a Kaehler and
hamiltonian G-manifold X. The supersymmetric N=2 theory can always be twisted
to produce a gauged A-model. This model localizes to the moduli space of
solutions of the vortex equations and computes the Hamiltonian Gromov-Witten
invariants. When the target is equivariantly Calabi-Yau, i.e. when its first
G-equivariant Chern class vanishes, the supersymmetric theory can also be
twisted into a gauged B-model. This model localizes to the Kaehler quotient
X//G.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 19:02:10 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Mar 2008 18:45:49 GMT"
}
] | 2009-04-30T00:00:00 | [
[
"Baptista",
"J. M.",
""
]
] |
0707.2787 | Arjen van der Wel | A. van der Wel, B. P. Holden, M. Franx, G. D. Illingworth, M. P.
Postman, D. D. Kelson, I. Labbe, S. Wuyts, J. P. Blakeslee, H. C. Ford | The Evolution of the Field and Cluster Morphology-Density Relation for
Mass-Selected Samples of Galaxies | 16 pages, 13 figures, 2 tables. Updated to match journal version.
Will appear in ApJ (vol. 670, p. 206) | null | 10.1086/521783 | null | astro-ph | null | The Sloan Digital Sky Survey (SDSS) and photometric/spectroscopic surveys in
the GOODS-South field (the Chandra Deep Field-South, CDFS) are used to
construct volume-limited, stellar mass-selected samples of galaxies at
redshifts 0<z<1. The CDFS sample at 0.6<z<1.0 contains 207 galaxies complete
down to M=4x10^10 Msol (for a ``diet'' Salpeter IMF), corresponding to a
luminosity limit for red galaxies of M_B=-20.1. The SDSS sample at
0.020<z<0.045 contains 2003 galaxies down to the same mass limit, which
corresponds to M_B=-19.3 for red galaxies. Morphologies are determined with an
automated method, using the Sersic parameter n and a measure of the residual
from the model fits, called ``bumpiness'', to distinguish different
morphologies. These classifications are verified with visual classifications.
In agreement with previous studies, 65-70% of the galaxies are located on the
red sequence, both at z~0.03 and at z~0.8. Similarly, 65-70% of the galaxies
have n>2.5. The fraction of E+S0 galaxies is 43+/-3%$ at z~0.03 and 48+/-7% at
z~0.8, i.e., it has not changed significantly since z~0.8. When combined with
recent results for cluster galaxies in the same redshift range, we find that
the morphology-density relation for galaxies more massive than 0.5M* has
remained constant since at least z~0.8. This implies that galaxies evolve in
mass, morphology and density such that the morphology-density relation does not
change. In particular, the decline of star formation activity and the
accompanying increase in the stellar mass density of red galaxies since z~1
must happen without large changes in the early-type galaxy fraction in a given
environment.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 19:11:29 GMT"
},
{
"version": "v2",
"created": "Thu, 1 Nov 2007 21:27:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"van der Wel",
"A.",
""
],
[
"Holden",
"B. P.",
""
],
[
"Franx",
"M.",
""
],
[
"Illingworth",
"G. D.",
""
],
[
"Postman",
"M. P.",
""
],
[
"Kelson",
"D. D.",
""
],
[
"Labbe",
"I.",
""
],
[
"Wuyts",
"S.",
""
],
[
"Blakeslee",
"J. P.",
""
],
[
"Ford",
"H. C.",
""
]
] |
0707.2788 | Georg von Hippel | Georg M. von Hippel, Randy Lewis and Robert G. Petry | Evolutionary Fitting Methods for the Extraction of Mass Spectra in
Lattice Field Theory | 39 pages, 7 figures; uses elsart.cls; version to appear in
Comput.Phys.Commun | Comput.Phys.Commun.178:713-723,2008 | 10.1016/j.cpc.2007.12.005 | null | hep-lat physics.comp-ph | null | We present an application of evolutionary algorithms to the curve-fitting
problems commonly encountered when trying to extract particle masses from
correlators in Lattice QCD. Harnessing the flexibility of evolutionary methods
in global optimization allows us to dynamically adapt the number of states to
be fitted along with their energies so as to minimize overall \chi^2/(d.o.f.),
leading to a promising new way of extracting the mass spectrum from measured
correlation functions.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 19:53:43 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Dec 2007 16:49:50 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"von Hippel",
"Georg M.",
""
],
[
"Lewis",
"Randy",
""
],
[
"Petry",
"Robert G.",
""
]
] |
0707.2789 | Marcus Kollar | Martin Eckstein and Marcus Kollar | Nonthermal steady states after an interaction quench in the
Falicov-Kimball model | 4 pages, 2 figures; published version | Phys. Rev. Lett. 100, 120404 (2008) | 10.1103/PhysRevLett.100.120404 | null | cond-mat.str-el cond-mat.stat-mech | null | We present the exact solution of the Falicov-Kimball model after a sudden
change of its interaction parameter using non-equilibrium dynamical mean-field
theory. For different interaction quenches between the homogeneous metallic and
insulating phases the system relaxes to a non-thermal steady state on time
scales on the order of hbar/bandwidth, showing collapse and revival with an
approximate period of h/interaction if the interaction is large. We discuss the
reasons for this behavior and provide a statistical description of the final
steady state by means of generalized Gibbs ensembles.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:00:10 GMT"
},
{
"version": "v2",
"created": "Tue, 8 Apr 2008 08:33:54 GMT"
}
] | 2008-04-08T00:00:00 | [
[
"Eckstein",
"Martin",
""
],
[
"Kollar",
"Marcus",
""
]
] |
0707.2790 | Sadegh Khochfar | S. Khochfar, J. Silk, R. A. Windhorst, R. E. Ryan Jr | The Evolving Faint-End of the Luminosity Function | 4 pages, replaced with version accepted to ApJL, minor changes to
figures | null | 10.1086/522790 | null | astro-ph | null | We investigate the evolution of the faint-end slope of the luminosity
function, $\alpha$, using semi-analytical modeling of galaxy formation. In
agreement with observations, we find that the slope can be fitted well by
$\alpha (z) =a+b z$, with a=-1.13 and b=-0.1. The main driver for the evolution
in $\alpha$ is the evolution in the underlying dark matter mass function.
Sub-L_* galaxies reside in dark matter halos that occupy a different part of
the mass function. At high redshifts, this part of the mass function is steeper
than at low redshifts and hence $\alpha$ is steeper. Supernova feedback in
general causes the same relative flattening with respect to the dark matter
mass function. The faint-end slope at low redshifts is dominated by field
galaxies and at high redshifts by cluster galaxies. The evolution of
$\alpha(z)$ in each of these environments is different, with field galaxies
having a slope b=-0.14 and cluster galaxies b=-0.05. The transition from
cluster-dominated to field-dominated faint-end slope occurs roughly at a
redshift $z_* \sim 2$, and suggests that a single linear fit to the overall
evolution of $\alpha(z)$ might not be appropriate. Furthermore, this result
indicates that tidal disruption of dwarf galaxies in clusters cannot play a
significant role in explaining the evolution of $\alpha(z)$ at z< z_*. In
addition we find that different star formation efficiencies a_* in the
Schmidt-Kennicutt-law and supernovae-feedback efficiencies $\epsilon$ generally
do not strongly influence the evolution of $\alpha(z)$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:01:42 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 10:12:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Khochfar",
"S.",
""
],
[
"Silk",
"J.",
""
],
[
"Windhorst",
"R. A.",
""
],
[
"Ryan",
"R. E.",
"Jr"
]
] |
0707.2791 | P. Q. Hung | P. Q. Hung | Shadow vacuum alignment and dark energy | RevTex, double columns, 5 pages | null | null | null | hep-ph astro-ph | null | In a recent model of dark energy (with several phenomenological
consequences), the universe is assumed to be trapped in a false vacuum with an
energy density of the order of (10^{-3} eV)^4, mimicking the presently
successful $\Lambda CDM$ scenario. This involves a new gauge group SU(2)_Z,
{\em the shadow sector}, which becomes strong at a scale $\Lambda_Z \sim
10^{-3} eV$. The model is described by the SU(2)_Z instanton-induced potential
of an axion-like scalar field, a_Z, with two degenerate vacuua. The false
(metastable) vacuum appears as a result of an phenomenological (ad-hoc) soft
breaking term linear in a_Z which explicitely breaks that degeneracy. In this
paper, we discuss a possible dynamical origin for this soft breaking term as
coming from the alignment of the vacuum along a direction in which the
condensate of the shadow fermions, $<\bar{\psi}^{(Z)}_{i} i \gamma_{5}
\psi^{(Z)}_{i}>$ which breaks spontaneously both P and CP, is non-vanishing.
The present universe lives in a vacuum which violates both P and CP in the
shadow SU(2)_Z sector!
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:02:14 GMT"
}
] | 2007-11-29T00:00:00 | [
[
"Hung",
"P. Q.",
""
]
] |
0707.2792 | Ivan Savov | David Avis, Patrick Hayden, Ivan Savov | Distributed Compression and Multiparty Squashed Entanglement | 26 pages, 6 figures thanks to jPicEdt. In v2 we fixed some typos and
made minor clarifications and updates | J. Phys. A 41 (2008) 115301 | 10.1088/1751-8113/41/11/115301 | null | quant-ph cs.IT math.IT | null | We study a protocol in which many parties use quantum communication to
transfer a shared state to a receiver without communicating with each other.
This protocol is a multiparty version of the fully quantum Slepian-Wolf
protocol for two senders and arises through the repeated application of the
two-sender protocol. We describe bounds on the achievable rate region for the
distributed compression problem. The inner bound arises by expressing the
achievable rate region for our protocol in terms of its vertices and extreme
rays and, equivalently, in terms of facet inequalities. We also prove an outer
bound on all possible rates for distributed compression based on the multiparty
squashed entanglement, a measure of multiparty entanglement.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:07:30 GMT"
},
{
"version": "v2",
"created": "Tue, 5 Feb 2008 19:39:29 GMT"
}
] | 2012-07-06T00:00:00 | [
[
"Avis",
"David",
""
],
[
"Hayden",
"Patrick",
""
],
[
"Savov",
"Ivan",
""
]
] |
0707.2793 | Ferdinando Patat | F. Patat, P. Chandra, R. Chevalier, S. Justham, Ph. Podsiadlowski, C.
Wolf, A. Gal-Yam, L. Pasquini, I.A. Crawford, P.A. Mazzali, A.W.A. Pauldrach,
K. Nomoto, S. Benetti, E. Cappellaro, N. Elias-Rosa, W. Hillebrandt, D.C.
Leonard, A. Pastorello, A. Renzini, F. Sabbadin, J.D. Simon and M. Turatto | Detection of circumstellar material in a normal Type Ia Supernova | 25 pages, 7 figures. Accepted for publication in Science. Full
resolution version at
http://www.hq.eso.org/~fpatat/science/sn06X/preprint.pdf . The original paper
can be found at http://www.sciencemag.org/cgi/content/abstract/1143005 | Science 317:924-926,2007 | 10.1126/science.1143005 | null | astro-ph | null | Type Ia supernovae are thought to be thermonuclear explosions of accreting
white dwarfs that reach a critical mass limit. Despite their importance as
cosmological distance indicators, the nature of their progenitors has remained
controversial. Here we report the detection of circumstellar material in a
normal Type Ia supernova. The expansion velocities, densities and dimensions of
the circumstellar envelope indicate that this material was ejected from the
progenitor system. The relatively low expansion velocities appear to favor a
progenitor system where a white dwarf accretes material from a companion star
which is in the red-giant phase at the time of explosion.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:13:29 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Patat",
"F.",
""
],
[
"Chandra",
"P.",
""
],
[
"Chevalier",
"R.",
""
],
[
"Justham",
"S.",
""
],
[
"Podsiadlowski",
"Ph.",
""
],
[
"Wolf",
"C.",
""
],
[
"Gal-Yam",
"A.",
""
],
[
"Pasquini",
"L.",
""
],
[
"Crawford",
"I. A.",
""
],
[
"Mazzali",
"P. A.",
""
],
[
"Pauldrach",
"A. W. A.",
""
],
[
"Nomoto",
"K.",
""
],
[
"Benetti",
"S.",
""
],
[
"Cappellaro",
"E.",
""
],
[
"Elias-Rosa",
"N.",
""
],
[
"Hillebrandt",
"W.",
""
],
[
"Leonard",
"D. C.",
""
],
[
"Pastorello",
"A.",
""
],
[
"Renzini",
"A.",
""
],
[
"Sabbadin",
"F.",
""
],
[
"Simon",
"J. D.",
""
],
[
"Turatto",
"M.",
""
]
] |
0707.2794 | Luis Herrera | A. Di Prisco, L. Herrera, G. Le Denmat, M.A.H. MacCallum, N.O. Santos | Nonadiabatic charged spherical gravitational collapse | 23 pages, Latex. To appear in Phys. Rev. D. Some references corrected | Phys.Rev.D76:064017,2007 | 10.1103/PhysRevD.76.064017 | null | gr-qc astro-ph | null | We present a complete set of the equations and matching conditions required
for the description of physically meaningful charged, dissipative, spherically
symmetric gravitational collapse with shear. Dissipation is described with both
free-streaming and diffusion approximations. The effects of viscosity are also
taken into account. The roles of different terms in the dynamical equation are
analyzed in detail. The dynamical equation is coupled to a causal transport
equation in the context of Israel-Stewart theory. The decrease of the inertial
mass density of the fluid, by a factor which depends on its internal
thermodynamic state, is reobtained, with the viscosity terms included. In
accordance with the equivalence principle, the same decrease factor is obtained
for the gravitational force term. The effect of the electric charge on the
relation between the Weyl tensor and the inhomogeneity of energy density is
discussed.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:17:02 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Aug 2007 19:37:00 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Di Prisco",
"A.",
""
],
[
"Herrera",
"L.",
""
],
[
"Denmat",
"G. Le",
""
],
[
"MacCallum",
"M. A. H.",
""
],
[
"Santos",
"N. O.",
""
]
] |
0707.2795 | Wei-Zhou Jiang | Wei-Zhou Jiang, Bao-An Li, and Lie-Wen Chen | Neutron-skin thickness of finite nuclei in relativistic mean-field
models with chiral limits | Accepted version to appear in PRC (2007) | PHys.Rev.C76:054314,2007 | 10.1103/PhysRevC.76.054314 | null | nucl-th | null | We study several structure properties of finite nuclei using relativistic
mean-field Lagrangians constructed according to the Brown-Rho scaling due to
the chiral symmetry restoration at high densities. The models are consistent
with current experimental constraints for the equations of state of symmetric
matter at both normal and supra-normal densities and of asymmetric matter at
sub-saturation densities. It is shown that these models can successfully
describe the binding energies and charge radii of finite nuclei. Compared to
calculations with usual relativistic mean-field models, these models give a
reduced thickness of neutron skin in ^{208}Pb between 0.17 fm and 0.21 fm. The
reduction of the predicted neutron skin thickness is found to be due to not
only the softening of the symmetry energy but also the scaling property of
$\rho $ meson required by the partial restoration of chiral symmetry.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:17:43 GMT"
},
{
"version": "v2",
"created": "Tue, 23 Oct 2007 16:12:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Jiang",
"Wei-Zhou",
""
],
[
"Li",
"Bao-An",
""
],
[
"Chen",
"Lie-Wen",
""
]
] |
0707.2796 | Florencia Graciela Leonardi Mrs | Pierre Collet, Antonio Galves and Florencia G. Leonardi | Random perturbations of stochastic chains with unbounded variable length
memory | null | null | null | null | math.PR | null | We consider binary infinite order stochastic chains perturbed by a random
noise. This means that at each time step, the value assumed by the chain can be
randomly and independently flipped with a small fixed probability. We show that
the transition probabilities of the perturbed chain are uniformly close to the
corresponding transition probabilities of the original chain. As a consequence,
in the case of stochastic chains with unbounded but otherwise finite variable
length memory, we show that it is possible to recover the context tree of the
original chain, using a suitable version of the algorithm Context, provided
that the noise is small enough.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:25:50 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Collet",
"Pierre",
""
],
[
"Galves",
"Antonio",
""
],
[
"Leonardi",
"Florencia G.",
""
]
] |
0707.2797 | Olivier Sarbach | Milton Ruiz, Oliver Rinne and Olivier Sarbach | Outer boundary conditions for Einstein's field equations in harmonic
coordinates | Added more details on specifying initial data and the numerical
calculation of reflection coefficients. 24 pages, 11 figures. To appear in
Classical and Quantum Gravity | Class.Quant.Grav.24:6349-6378,2007 | 10.1088/0264-9381/24/24/012 | null | gr-qc | null | We analyze Einstein's vacuum field equations in generalized harmonic
coordinates on a compact spatial domain with boundaries. We specify a class of
boundary conditions which is constraint-preserving and sufficiently general to
include recent proposals for reducing the amount of spurious reflections of
gravitational radiation. In particular, our class comprises the boundary
conditions recently proposed by Kreiss and Winicour, a geometric modification
thereof, the freezing-Psi0 boundary condition and the hierarchy of absorbing
boundary conditions introduced by Buchman and Sarbach. Using the recent
technique developed by Kreiss and Winicour based on an appropriate reduction to
a pseudo-differential first order system, we prove well posedness of the
resulting initial-boundary value problem in the frozen coefficient
approximation. In view of the theory of pseudo-differential operators it is
expected that the full nonlinear problem is also well posed. Furthermore, we
implement some of our boundary conditions numerically and study their
effectiveness in a test problem consisting of a perturbed Schwarzschild black
hole.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:28:38 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 16:41:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ruiz",
"Milton",
""
],
[
"Rinne",
"Oliver",
""
],
[
"Sarbach",
"Olivier",
""
]
] |
0707.2798 | Mark Allen | The BABAR Collaboration, B. Aubert, et al | Study of B0 -> pi0 pi0, B -> pi pi0, and B -> K pi0 Decays, and Isospin
Analysis of B -> pipi Decays | 8 pages, 3 figures, submitted to Phys. Rev. D (Rapid Communications) | Phys.Rev.D76:091102,2007 | 10.1103/PhysRevD.76.091102 | SLAC-PUB-12682 | hep-ex | null | We present updated measurements of the branching fractions and CP asymmetries
for B0 -> pi0 pi0, B+ -> pi+ pi0, and B+ -> K+ pi0. Based on a sample of 383 x
10^6 Upsilon(4S) -> B Bbar decays collected by the BABAR detector at the PEP-II
asymmetric-energy B factory at SLAC, we measure B(B0 -> pi0 pi0) =(1.47 +/-
0.25 +/- 0.12) x 10^-6, B(B+ -> pi+ pi0)= (5.02 +/- 0.46 +/- 0.29) x 10^-6, and
B(B+ -> K+ pi0) = (13.6 +/- 0.6 +/- 0.7) x 10^-6. We also measure the CP
asymmetries C(pi0 pi0) = -0.49 +/- 0.35 +/- 0.05, A(pi+ pi0) = 0.03 +/- 0.08
+/- 0.01, and A(K+ pi0) = 0.030 +/- 0.039 +/- 0.010. Finally, we present bounds
on the CKM angle $\alpha$ using isospin relations.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:29:37 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.2799 | Yang Zhao | Y. Zhao, B. D. Gaulin, J. P. Castellan, J. P. C. Ruff, S. R. Dunsiger,
G. D. Gu, and H. A. Dabkowska | High resolution X-ray scattering studies of structural phase transitions
in underdoped La$_{2-x}$Ba$_x$CuO$_4$ | 8 pages, 7 figures, 1 table | null | 10.1103/PhysRevB.76.184121 | null | cond-mat.supr-con | null | We have studied structural phase transitions in high quality underdoped
La$_{2-x}$Ba$_x$CuO$_4$ single crystals using high resolution x-ray scattering
techniques. Critical properties associated with the continuous High Temperature
Tetragonal (HTT, $I4/mmm$) to Middle Temperature Orthorhombic (MTO, $Cmca$)
phase transition were investigated in single crystal samples with x=0.125,
0.095, and 0.08 and we find that all behavior is consistent with three
dimensional XY criticality, as expected from theory. Power law behavior in the
orthorhombic strain, 2(a-b)/(a+b), is observed over a remarkably wide
temperature range, spanning most of the MTO regime in the phase diagram. Low
temperature measurements investigating the Low Temperature Tetragonal (LTT,
$P4_{2}/ncm$) phase, below the strongly discontinuous MTO$\to$LTT phase
transition, in x=0.125 and x=0.095 samples show that the LTT phase is
characterized by relatively broad Bragg scattering, compared with that observed
at related wavevectors in the HTT phase. This shows that the LTT phase is
either an admixture of tetragonal and orthorhombic phases, or that it is
orthorhombic with very small orthorhombic strain, consistent with the ``less
orthorhombic" low temperature structure previously reported in mixed
La$_{2-x}$Sr$_{x-y}$Ba$_y$CuO$_4$ single crystals. We compare the complex
temperature-composition phase diagram for the location of structural and
superconducting phase transitions in underdoped La$_{2-x}$Ba$_x$CuO$_4$ and
find good agreement with results obtained on polycrystalline samples.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:40:26 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhao",
"Y.",
""
],
[
"Gaulin",
"B. D.",
""
],
[
"Castellan",
"J. P.",
""
],
[
"Ruff",
"J. P. C.",
""
],
[
"Dunsiger",
"S. R.",
""
],
[
"Gu",
"G. D.",
""
],
[
"Dabkowska",
"H. A.",
""
]
] |
0707.2800 | Peter Lunkenheimer | L.C. Pardo, P. Lunkenheimer, and A. Loidl | Dielectric spectroscopy in benzophenone: The beta relaxation and its
relation to the mode-coupling Cole-Cole peak | 4 pages, 3 figures; second version as published; small changes of
text according to referee suggestions; title changed according to editor's
demands | Phys. Rev. E 76, 030502(R) (2007) | 10.1103/PhysRevE.76.030502 | null | cond-mat.dis-nn cond-mat.soft | null | We report a thorough characterization of the glassy dynamics of benzophenone
by broadband dielectric spectroscopy. We detect a well pronounced beta
relaxation peak developing into an excess wing with increasing temperature. A
previous analysis of results from Optical-Kerr-effect measurements on this
material within the mode coupling theory revealed a high-frequency Cole-Cole
peak. We address the question if this phenomenon also may explain the
Johari-Goldstein beta relaxation, a so far unexplained spectral feature
inherent to glass-forming matter, mainly observed in dielectric spectra. Our
results demonstrate that according to the present status of theory, both
spectral features seem not to be directly related.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:54:43 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Oct 2007 18:30:13 GMT"
}
] | 2007-10-08T00:00:00 | [
[
"Pardo",
"L. C.",
""
],
[
"Lunkenheimer",
"P.",
""
],
[
"Loidl",
"A.",
""
]
] |
0707.2801 | D. F. Mota | P. Brax, C. van de Bruck, A. C. Davis, D. F. Mota, D. J. Shaw | Testing Chameleon Theories with Light Propagating through a Magnetic
Field | 24 pages, 6 figures. New paragraph and two extra plots with the
predictions for Chameleon models within the BRFT experimental setup. Accepted
for publication in Phys. Rev. D | Phys.Rev.D76:085010,2007 | 10.1103/PhysRevD.76.085010 | null | hep-ph astro-ph gr-qc hep-th | null | It was recently argued that the observed PVLAS anomaly can be explained by
chameleon field theories in which large deviations from Newton's law can be
avoided. Here we present the predictions for the dichroism and the
birefringence induced in the vacuum by a magnetic field in these models. We
show that chameleon particles behave very differently from standard axion-like
particles (ALPs). We find that, unlike ALPs, the chameleon particles are
confined within the experimental set-up. As a consequence, the birefringence is
always bigger than the dichroism in PVLAS-type experiments.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:14:06 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 22:52:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Brax",
"P.",
""
],
[
"van de Bruck",
"C.",
""
],
[
"Davis",
"A. C.",
""
],
[
"Mota",
"D. F.",
""
],
[
"Shaw",
"D. J.",
""
]
] |
0707.2802 | Arjen van der Meer | A. van der Meer, L. Kaper, M. H. van Kerkwijk, M. H. M. Heemskerk,
E.P.J. van den Heuvel | Determination of the mass of the neutron star in SMC X-1, LMC X-4 and
Cen X-3 with VLT/UVES | Accepted for publication in Astronomy and Astrophysics | null | 10.1051/0004-6361:20066025 | null | astro-ph | null | We present the results of a spectroscopic monitoring campaign of the OB-star
companions to the eclipsing X-ray pulsars SMC X-1, LMC X-4 and Cen X-3.
High-resolution optical spectra obtained with UVES on the ESO Very Large
Telescope are used to determine the radial-velocity orbit of the OB
(super)giants with high precision. The excellent quality of the spectra
provides the opportunity to measure the radial-velocity curve based on
individual lines, and to study the effect of possible distortions of the line
profiles due to e.g. X-ray heating on the derived radial-velocity amplitude.
Several spectral lines show intrinsic variations with orbital phase. The
magnitude of these variations depends on line strength, and thus provides a
criterion to select lines that do not suffer from distortions. The undistorted
lines show a larger radial-velocity amplitude than the distorted lines,
consistent with model predictions. Application of our line-selection criteria
results in a mean radial-velocity amplitude K(Opt) of 20.2 +/- 1.1, 35.1 +/-
1.5, and 27.5 +/- 2.3 km/s (1 sigma errors), for the OB companion to SMC X-1,
LMC X-4 and Cen X-3, respectively. Adding information on the projected
rotational velocity of the OB companion (derived from our spectra), the
duration of X-ray eclipse and orbital parameters of the X-ray pulsar (obtained
from literature), we arrive at a neutron star mass of 1.06^{+0.11}_{-0.10},
1.25^{+0.11}_{-0.10} and 1.34^{+0.16}_{-0.14} M{sun} for SMC X-1, LMC X-4 and
Cen X-3, respectively. The mass of SMC X-1 is near the minimum mass (~1 M{sun})
expected for a neutron star produced in a supernova. We discuss the
implications of the measured mass distribution on the neutron-star formation
mechanism, in relation to the evolutionary history of the massive binaries.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:45:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"van der Meer",
"A.",
""
],
[
"Kaper",
"L.",
""
],
[
"van Kerkwijk",
"M. H.",
""
],
[
"Heemskerk",
"M. H. M.",
""
],
[
"Heuvel",
"E. P. J. van den",
""
]
] |
0707.2803 | Jean-Sebastien Caux | R. Hagemans and J.-S. Caux | Deformed strings in the Heisenberg model | 34 pages, 13 figures | J. Phys. A: Math. Theor. 40 (2007) 14605-14647 | 10.1088/1751-8113/40/49/001 | null | cond-mat.str-el cond-mat.stat-mech hep-th | null | We investigate solutions to the Bethe equations for the isotropic S = 1/2
Heisenberg chain involving complex, string-like rapidity configurations of
arbitrary length. Going beyond the traditional string hypothesis of undeformed
strings, we describe a general procedure to construct eigenstates including
strings with generic deformations, discuss general features of these solutions,
and provide a number of explicit examples including complete solutions for all
wavefunctions of short chains. We finally investigate some singular cases and
show from simple symmetry arguments that their contribution to zero-temperature
correlation functions vanishes.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:29:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hagemans",
"R.",
""
],
[
"Caux",
"J. -S.",
""
]
] |
0707.2804 | Misha Katsnelson | M. Auslender and M. I. Katsnelson | Generalized kinetic equations for charge carriers in graphene | final version, Phys. Rev. B, accepted | Phys. Rev. B 76, 235425 (2007) | 10.1103/PhysRevB.76.235425 | null | cond-mat.mes-hall cond-mat.stat-mech | null | A system of generalized kinetic equations for the distribution functions of
two-dimensional Dirac fermions scattered by impurities is derived in the Born
approximation with respect to short-range impurity potential. It is proven that
the conductivity following from classical Boltzmann equation picture, where
electrons or holes have scattering amplitude reduced due chirality, is
justified except for an exponentially narrow range of chemical potential near
the conical point. When in this range, creation of infinite number of
electron-hole pairs related to quasi-relativistic nature of electrons in
graphene results in a renormalization of minimal conductivity as compared to
the Boltzmann term and logarithmic corrections in the conductivity similar to
the Kondo effect.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:36:40 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 10:00:44 GMT"
}
] | 2011-01-14T00:00:00 | [
[
"Auslender",
"M.",
""
],
[
"Katsnelson",
"M. I.",
""
]
] |
0707.2805 | Igor Zutic | Ramin M. Abolfath, Andre Petukhov and Igor Zutic | Piezomagnetic Quantum Dots | 4 pages, 3 figures | Phys. Rev. Lett. 101, 207202 (2008); minor changes | 10.1103/PhysRevLett.101.207202 | null | cond-mat.mes-hall cond-mat.mtrl-sci | null | We study the influence of deformations on magnetic ordering in quantum dots
doped with magnetic impurities. The reduction of symmetry and the associated
deformation from circular to elliptical quantum confinement lead to the
formation of piezomagnetic quantum dots. The strength of elliptical deformation
can be controlled by the gate voltage to change the magnitude of magnetization,
at a fixed number of carriers and in the absence of applied magnetic field. We
reveal a reentrant magnetic ordering with the increase of elliptical
deformation and suggest that the piezomagnetic quantum dots can be used as
nanoscale magnetic switches.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 20:53:43 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Abolfath",
"Ramin M.",
""
],
[
"Petukhov",
"Andre",
""
],
[
"Zutic",
"Igor",
""
]
] |
0707.2806 | Yong Shi | Yong Shi, Patrick Ogle, George H. Rieke, Robert Antonucci, Dean C.
Hines, Paul S. Smith, Frank J. Low, Jeroen Bouwman, Christopher Willmer | Aromatic Features in AGN: Star-Forming Infrared Luminosity Function of
AGN Host Galaxies | Accepted for publication in ApJ, 24 pages, 13 figures | Astrophys.J. 669(2007) 841 | 10.1086/521594 | null | astro-ph | null | We describe observations of aromatic features at 7.7 and 11.3 um in AGN of
three types including PG, 2MASS and 3CR objects. The feature has been
demonstrated to originate predominantly from star formation. Based on the
aromatic-derived star forming luminosity, we find that the far-IR emission of
AGN can be dominated by either star formation or nuclear emission; the average
contribution from star formation is around 25% at 70 and 160 um. The
star-forming infrared luminosity functions of the three types of AGN are
flatter than that of field galaxies, implying nuclear activity and star
formation tend to be enhanced together. The star-forming luminosity function is
also a function of the strength of nuclear activity from normal galaxies to the
bright quasars, with luminosity functions becoming flatter for more intense
nuclear activity. Different types of AGN show different distributions in the
level of star formation activity, with 2MASS> PG> 3CR star formation rates.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:01:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Shi",
"Yong",
""
],
[
"Ogle",
"Patrick",
""
],
[
"Rieke",
"George H.",
""
],
[
"Antonucci",
"Robert",
""
],
[
"Hines",
"Dean C.",
""
],
[
"Smith",
"Paul S.",
""
],
[
"Low",
"Frank J.",
""
],
[
"Bouwman",
"Jeroen",
""
],
[
"Willmer",
"Christopher",
""
]
] |
0707.2807 | Giuseppe Vallone Dr. | Giuseppe Vallone, Enrico Pomarico, Paolo Mataloni, Francesco De
Martini, Marco Barbieri | Experimental Realization of Polarization Qutrits from Non-Maximally
Entangled States | RevTex, 8 pages, 6 figures | Phys. Rev. A 76, 012319 (2007) | 10.1103/PhysRevA.76.012319 | null | quant-ph | null | Based on a recent proposal [Phys. Rev. A 71, 062337 (2005)], we have
experimentally realized two photon polarization qutrits by using non-maximally
entangled states and linear optical transformations. By this technique high
fidelity mutually unbiased qutrits are generated at a high brilliance level.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:00:44 GMT"
}
] | 2008-11-05T00:00:00 | [
[
"Vallone",
"Giuseppe",
""
],
[
"Pomarico",
"Enrico",
""
],
[
"Mataloni",
"Paolo",
""
],
[
"De Martini",
"Francesco",
""
],
[
"Barbieri",
"Marco",
""
]
] |
0707.2808 | Elina Lindfors | E. J. Lindfors, M. T\"urler, D. C. Hannikainen, G. Pooley, J. Tammi,
S. A. Trushkin and E. Valtaoja | Synchrotron flaring behaviour of CygnusX-3 during the February-March
1994 and September 2001 outbursts | 8 pages, 3 figures, accepted for publication in Astronomy and
Astrophysics | null | 10.1051/0004-6361:20077620 | null | astro-ph | null | Aims: In this paper we study whether the shock-in-jet model, widely used to
explain the outbursting behaviour of quasars, can be used to explain the radio
flaring behaviour of the microquasar Cygnus X-3.
Method: We have used a method developed to model the synchrotron outbursts of
quasar jets, which decomposes multifrequency lightcurves into a series of
outbursts. The method is based on the Marscher & Gear (1985) shock model, but
we have implemented the modifications to the model suggested by Bjornsson &
Aslaksen (2000), which make the flux density increase in the initial phase less
abrupt. We study the average outburst evolution as well as specific
characteristics of individual outbursts and physical jet properties of Cyg X-3.
Results: We find that the lightcurves of the February-March 1994 and
September 2001 outbursts can be described with the modified shock model. The
average evolution shows that instead of the expected synchrotron plateau, the
flux density is still increasing during the synchrotron stage. We also find
that high frequency peaking outbursts are shorter in duration than the ones
peaking at lower frequencies. Finally, we show that the method can be used,
complementary to radio interferometric jet imaging, for deriving the physical
parameters such as the magnetic field strength and the energy density of
relativistic electrons in the jet of Cyg X-3.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:25:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lindfors",
"E. J.",
""
],
[
"Türler",
"M.",
""
],
[
"Hannikainen",
"D. C.",
""
],
[
"Pooley",
"G.",
""
],
[
"Tammi",
"J.",
""
],
[
"Trushkin",
"S. A.",
""
],
[
"Valtaoja",
"E.",
""
]
] |
0707.2809 | Koji Nagata | Koji Nagata | Multipartite positive-partial-transpose inequalities exponentially
stronger than local reality inequalities | 4 pages, To appear in Phys. Rev. A | Phys. Rev. A 76, 024101 (2007) | 10.1103/PhysRevA.76.024101 | null | quant-ph | null | We show that positivity of {\it every} partial transpose of $N$-partite
quantum states implies new inequalities on Bell correlations which are stronger
than standard Bell inequalities by a factor of $2^{(N-1)/2}$. A violation of
the inequality implies the system is in a bipartite distillable entangled
state. It turns out that a family of $N$-qubit bound entangled states proposed
by D\"ur {[Phys. Rev. Lett. {\bf 87}, 230402 (2001)]} violates the inequality
for $N\geq 4$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:13:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Nagata",
"Koji",
""
]
] |
0707.2810 | Manfred Salmhofer | Walter Pedra and Manfred Salmhofer | Determinant Bounds and the Matsubara UV Problem of Many-Fermion Systems | 29 pages LaTeX | null | 10.1007/s00220-008-0463-z | null | math-ph cond-mat.str-el math.MP | null | It is known that perturbation theory converges in fermionic field theory at
weak coupling if the interaction and the covariance are summable and if certain
determinants arising in the expansion can be bounded efficiently, e.g. if the
covariance admits a Gram representation with a finite Gram constant. The
covariances of the standard many--fermion systems do not fall into this class
due to the slow decay of the covariance at large Matsubara frequency, giving
rise to a UV problem in the integration over degrees of freedom with Matsubara
frequencies larger than some Omega (usually the first step in a multiscale
analysis). We show that these covariances do not have Gram representations on
any separable Hilbert space. We then prove a general bound for determinants
associated to chronological products which is stronger than the usual Gram
bound and which applies to the many--fermion case. This allows us to prove
convergence of the first integration step in a rather easy way, for a
short--range interaction which can be arbitrarily strong, provided Omega is
chosen large enough. Moreover, we give - for the first time - nonperturbative
bounds on all scales for the case of scale decompositions of the propagator
which do not impose cutoffs on the Matsubara frequency.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:19:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pedra",
"Walter",
""
],
[
"Salmhofer",
"Manfred",
""
]
] |
0707.2811 | Carles Rod\'o | C. Rod\'o, Gerardo Adesso, A. Sanpera | Operational Quantification of Continuous Variable Correlations | 4 pages, 3 figures, improved presentation, a subfigure and some
explicit analytical expressions added | Phys. Rev. Lett. 100, 110505 (2008) | 10.1103/PhysRevLett.100.110505 | null | quant-ph | null | We quantify correlations (quantum and/or classical) between two continuous
variable modes in terms of how many correlated bits can be extracted by
measuring the sign of two local quadratures. On Gaussian states, such `bit
quadrature correlations' majorize entanglement, reducing to an entanglement
monotone for pure states. For non-Gaussian states, such as photonic Bell
states, ideal and real de-Gaussified photon-subtracted states, and mixtures of
pure Gaussian states, the bit correlations are shown to be a {\em monotonic}
function of the negativity. This yields a feasible, operational way to
quantitatively measure non-Gaussian entanglement in current experiments by
means of direct homodyne detection, without a full tomographical reconstruction
of the Wigner function.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:21:51 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Nov 2007 17:44:55 GMT"
}
] | 2008-03-24T00:00:00 | [
[
"Rodó",
"C.",
""
],
[
"Adesso",
"Gerardo",
""
],
[
"Sanpera",
"A.",
""
]
] |
0707.2812 | Stephen P. Martin | Stephen P. Martin | The top squark-mediated annihilation scenario and direct detection of
dark matter in compressed supersymmetry | 17 pages. v2: additions to figures 4 and 6 | Phys.Rev.D76:095005,2007 | 10.1103/PhysRevD.76.095005 | null | hep-ph | null | Top squark-mediated annihilation of bino-like neutralinos to top-antitop
pairs can play the dominant role in obtaining a thermal relic dark matter
abundance in agreement with observations. In a previous paper, it was argued
that this can occur naturally in models of compressed supersymmetry, which
feature a running gluino mass parameter that is substantially smaller than the
wino mass parameter at the scale of apparent gauge coupling unification. Here I
study in some more detail the parameter space in which this is viable, and
compare to other scenarios for obtaining the observed dark matter density. I
then study the possibility of detecting the dark matter directly in future
experiments. The prospects are consistently very promising for a wide variety
of model parameters within this scenario.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 21:46:20 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Sep 2007 03:20:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Martin",
"Stephen P.",
""
]
] |
0707.2813 | Patrik L. Ferrari | Alexei Borodin (1), Patrik L. Ferrari (2) ((1) Caltech, (2) WIAS
Berlin) | Large time asymptotics of growth models on space-like paths I: PushASEP | 48 pages, 4 figures, LaTeX; Final version | Electron. J. Probab. 13 (2008), 1380-1418 | null | null | math-ph cond-mat.stat-mech math.MP math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a new interacting particle system on the one-dimensional lattice
that interpolates between TASEP and Toom's model: A particle cannot jump to the
right if the neighboring site is occupied, and when jumping to the left it
simply pushes all the neighbors that block its way.
We prove that for flat and step initial conditions, the large time
fluctuations of the height function of the associated growth model along any
space-like path are described by the Airy_1 and Airy_2 processes. This includes
fluctuations of the height profile for a fixed time and fluctuations of a
tagged particle's trajectory as special cases.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 22:12:16 GMT"
},
{
"version": "v2",
"created": "Mon, 20 Aug 2007 08:25:53 GMT"
},
{
"version": "v3",
"created": "Sat, 14 Jun 2008 10:13:18 GMT"
},
{
"version": "v4",
"created": "Wed, 13 Aug 2008 09:36:49 GMT"
}
] | 2008-11-01T00:00:00 | [
[
"Borodin",
"Alexei",
""
],
[
"Ferrari",
"Patrik L.",
""
]
] |
0707.2814 | Xinjia Chen | Xinjia Chen | Coverage Probability of Random Intervals | 21 pages, 2 figure, revised Theorem 7 | null | null | null | math.ST math.PR stat.ME stat.TH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we develop a general theory on the coverage probability of
random intervals defined in terms of discrete random variables with continuous
parameter spaces. The theory shows that the minimum coverage probabilities of
random intervals with respect to corresponding parameters are achieved at
discrete finite sets and that the coverage probabilities are continuous and
unimodal when parameters are varying in between interval endpoints. The theory
applies to common important discrete random variables including binomial
variable, Poisson variable, negative binomial variable and hypergeometrical
random variable. The theory can be used to make relevant statistical inference
more rigorous and less conservative.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:19:17 GMT"
},
{
"version": "v10",
"created": "Thu, 17 Sep 2009 21:56:14 GMT"
},
{
"version": "v11",
"created": "Sun, 13 Mar 2011 23:18:24 GMT"
},
{
"version": "v12",
"created": "Wed, 16 Mar 2011 04:53:41 GMT"
},
{
"version": "v13",
"created": "Mon, 11 Apr 2011 01:24:21 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 18:02:16 GMT"
},
{
"version": "v3",
"created": "Mon, 23 Jul 2007 18:56:07 GMT"
},
{
"version": "v4",
"created": "Wed, 1 Aug 2007 00:10:01 GMT"
},
{
"version": "v5",
"created": "Tue, 7 Aug 2007 09:45:45 GMT"
},
{
"version": "v6",
"created": "Sat, 25 Aug 2007 21:30:35 GMT"
},
{
"version": "v7",
"created": "Mon, 3 Sep 2007 00:53:34 GMT"
},
{
"version": "v8",
"created": "Thu, 19 Jun 2008 18:38:17 GMT"
},
{
"version": "v9",
"created": "Sun, 3 Aug 2008 00:43:25 GMT"
}
] | 2011-04-12T00:00:00 | [
[
"Chen",
"Xinjia",
""
]
] |
0707.2815 | David Hanna | T. Lindner, D.S. Hanna, J. Kildea, J.Ball, D.A. Bramel, J. Carson,
C.E. Covault, D. Driscoll, P. Fortin, D.M. Gingrich, A. Jarvis, C. Mueller,
R. Mukherjee, R.A. Ong, K. Ragan, R.A. Scalzo, D.A. Williams, J. Zweerink | Very high energy observations of the BL Lac objects 3C 66A and OJ 287 | 24 pages, 15 figures, Accepted for publication in Astroparticle
Physics | Astropart.Phys.28:338-347,2007 | 10.1016/j.astropartphys.2007.07.001 | null | astro-ph | null | Using the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE), we
have observed the BL Lac objects 3C 66A and OJ 287. These are members of the
class of low-frequency-peaked BL Lac objects (LBLs) and are two of the three
LBLs predicted by Costamante and Ghisellini to be potential sources of very
high energy (>100 GeV) gamma-ray emission. The third candidate, BL Lacertae,
has recently been detected by the MAGIC collaboration. Our observations have
not produced detections; we calculate a 99% CL upper limit of flux from 3C 66A
of 0.15 Crab flux units and from OJ 287 our limit is 0.52 Crab. These limits
assume a Crab-like energy spectrum with an effective energy threshold of 185
GeV.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 22:27:00 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lindner",
"T.",
""
],
[
"Hanna",
"D. S.",
""
],
[
"Kildea",
"J.",
""
],
[
"Ball",
"J.",
""
],
[
"Bramel",
"D. A.",
""
],
[
"Carson",
"J.",
""
],
[
"Covault",
"C. E.",
""
],
[
"Driscoll",
"D.",
""
],
[
"Fortin",
"P.",
""
],
[
"Gingrich",
"D. M.",
""
],
[
"Jarvis",
"A.",
""
],
[
"Mueller",
"C.",
""
],
[
"Mukherjee",
"R.",
""
],
[
"Ong",
"R. A.",
""
],
[
"Ragan",
"K.",
""
],
[
"Scalzo",
"R. A.",
""
],
[
"Williams",
"D. A.",
""
],
[
"Zweerink",
"J.",
""
]
] |
0707.2816 | Delfim F. M. Torres | Moulay Rchid Sidi Ammi, Delfim F. M. Torres | Regularity of solutions to higher-order integrals of the calculus of
variations | null | International Journal of Systems Science, Vol. 39, No. 9, pp.
889--895, 2008 | 10.1080/00207720802184733 | null | math.OC | null | We obtain new regularity conditions for problems of calculus of variations
with higher-order derivatives. As a corollary, we get non-occurrence of the
Lavrentiev phenomenon. Our main regularity result asserts that autonomous
integral functionals with a Lagrangian having coercive partial derivatives with
respect to the higher-order derivatives admit only minimizers with essentially
bounded derivatives.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 22:36:31 GMT"
}
] | 2008-07-19T00:00:00 | [
[
"Ammi",
"Moulay Rchid Sidi",
""
],
[
"Torres",
"Delfim F. M.",
""
]
] |
0707.2817 | J\'anos Pipek | J. Pipek and Sz. Nagy | The kinetic energy operator in the subspaces of wavelet analysis | null | null | null | null | physics.chem-ph physics.comp-ph | null | At any resolution level of wavelet expansions the physical observable of the
kinetic energy is represented by an infinite matrix which is ``canonically''
chosen as the projection of the operator $-\Delta/2$ onto the subspace of the
given resolution. It is shown, that this canonical choice is not optimal, as
the regular grid of the basis set introduces an artificial consequence of
periodicity, and it is only a particular member of possible operator
representations. We present an explicit method of preparing a near optimal
kinetic energy matrix which leads to more appropriate results in numerical
wavelet based calculations. This construction works even in those cases, where
the usual definition is unusable (i.e., the derivative of the basis functions
does not exist). It is also shown, that building an effective kinetic energy
matrix is equivalent to the renormalization of the kinetic energy by a momentum
dependent effective mass compensating for artificial periodicity effects.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 22:48:04 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Pipek",
"J.",
""
],
[
"Nagy",
"Sz.",
""
]
] |
0707.2818 | Giles Novak | G. Novak, J. L. Dotson, and H. Li | Dispersion of Observed Position Angles of Submillimeter Polarization in
Molecular Clouds | revised, accepted version; to appear in The Astrophysical Journal; 20
pages, 2 figures, 2 tables | Astrophys.J.695:1362-1369,2009 | 10.1088/0004-637X/695/2/1362 | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | One can estimate the characteristic magnetic field strength in GMCs by
comparing submillimeter polarimetric observations of these sources with
simulated polarization maps developed using a range of different values for the
assumed field strength. The point of comparison is the degree of order in the
distribution of polarization position angles. In a recent paper by H. Li and
collaborators, such a comparison was carried out using SPARO observations of
two GMCs, and employing simulations by E. Ostriker and collaborators. Here we
reexamine this same question, using the same data set and the same simulations,
but using an approach that differs in several respects. The most important
difference is that we incorporate new, higher angular resolution observations
for one of the clouds, obtained using the Hertz polarimeter. We conclude that
the agreement between observations and simulations is best when the total
magnetic energy (including both uniform and fluctuating field components) is at
least as large as the turbulent kinetic energy.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 23:07:33 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Jan 2009 21:48:58 GMT"
}
] | 2009-04-17T00:00:00 | [
[
"Novak",
"G.",
""
],
[
"Dotson",
"J. L.",
""
],
[
"Li",
"H.",
""
]
] |
0707.2819 | Dirk Puetzfeld | Dirk Puetzfeld, Yuri N. Obukhov | Propagation equations for deformable test bodies with microstructure in
extended theories of gravity | 27 pages, 1 figure, matches published version including the erratum
in Phys. Rev. D 79 (2009) 069902(E) | Phys.Rev.D76:084025,2007; Erratum-ibid.D79:069902,2009 | 10.1103/PhysRevD.76.084025 10.1103/PhysRevD.79.069902 | null | gr-qc astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We derive the equations of motion in metric-affine gravity by making use of
the conservation laws obtained from Noether's theorem. The results are given in
the form of propagation equations for the multipole decomposition of the matter
sources in metric-affine gravity, i.e., the canonical energy-momentum current
and the hypermomentum current. In particular, the propagation equations allow
for a derivation of the equations of motion of test particles in this
generalized gravity theory, and allow for direct identification of the
couplings between the matter currents and the gauge gravitational field
strengths of the theory, namely, the curvature, the torsion, and the
nonmetricity. We demonstrate that the possible non-Riemannian spacetime
geometry can only be detected with the help of the test bodies that are formed
of matter with microstructure. Ordinary gravitating matter, i.e., matter
without microscopic internal degrees of freedom, can probe only the Riemannian
spacetime geometry. Thereby, we generalize previous results of general
relativity and Poincare gauge theory.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 23:42:43 GMT"
},
{
"version": "v2",
"created": "Sun, 18 Nov 2007 13:37:34 GMT"
},
{
"version": "v3",
"created": "Mon, 30 Mar 2009 10:56:27 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Puetzfeld",
"Dirk",
""
],
[
"Obukhov",
"Yuri N.",
""
]
] |
0707.2820 | Vyacheslav Krutelyov | V. Krutelyov (for the CDF Collaboration and the D0 Collaboration) | Rare decays of heavy flavor at the Tevatron | in proceedings of Hadron Collider Physics Symposium, Duke University,
NC, May 22-26 2006 | null | null | null | hep-ex | null | In this report I review recent results in the field of rare decays at the
Tevatron CDF II and D0 experiments. The presentation is focused on rare decays
of charm and bottom mesons with two muons in the final state. This includes
improvements over the previously available limits on the following branching
ratios: $B(D^+ \to \pi^+ \mu^+ \mu^-)< 4.7 \times 10^{-6}$, B(B_s^0 \to \phi
\mu^+ \mu^-)< 3.2\times 10^{-6}$, $B(B_s^0 \to \mu^+ \mu^-)< 1 \times 10^{-7}$,
and $B(B_d^0)< 3 \times 10{-8}$ all at the 90% confidence level. Also reported
are the first direct observation of $D_s^+ \to \phi \pi^+ \to \mu^+ \mu^-
\pi^+$ with a significance above background of over 7 standard deviations and
evidence of $D^+ \to \phi \pi^+ \to \mu^+ \mu^- \pi^+$ with a significance of
3.1 and $B(D^+ \to \phi \pi^+ \to \mu^+ \mu^- \pi^+)=(1.75 \pm0.7 \pm0.5)
\times 10^{-6}$.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 23:31:56 GMT"
}
] | 2019-08-14T00:00:00 | [
[
"Krutelyov",
"V.",
"",
"for the CDF Collaboration and the D0 Collaboration"
]
] |
0707.2821 | Alexey Veryaskin | Alexey Veryaskin and Wayne McRae | On the combined gravity gradient modeling for applied geophysics | 17 pages,11 figures, this version has been modified for publication
in the Journal of Geophysics and Engineering | null | 10.1088/1742-2132/5/3/010 | Preprint GG1-07 | physics.geo-ph physics.ins-det | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Gravity gradiometry research and development has intensified in recent years
to the extent that technologies providing a resolution of about 1 Eotvos per 1
sec average shall likely soon be available for multiple critical applications
such as natural resources exploration, oil reservoir monitoring and defence
establishment. Much of the content of this paper was composed a decade ago, and
only minor modifications were required for the conclusions to be just as
applicable today. In this paper we demonstrate how gravity gradient data can be
modeled, and show some examples of how gravity gradient data can be combined in
order to extract valuable information. In particular, this study demonstrates
the importance of two gravity gradient components, Txz and Tyz which, when
processed together, can provide more information on subsurface density
contrasts than that derived solely from the vertical gravity gradient (Tzz).
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 00:40:42 GMT"
},
{
"version": "v2",
"created": "Thu, 3 Jul 2008 03:15:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Veryaskin",
"Alexey",
""
],
[
"McRae",
"Wayne",
""
]
] |
0707.2822 | Andrew Francis | Andrew Francis | Centralizers in the Hecke algebras of complex reflection groups | 40 pages. 11 figures. This paper was submitted in December 2004 | null | null | null | math.RT | null | How far can the elementary description of centralizers of parabolic
subalgebras of Hecke algebras of finite real reflection groups be generalized
to the complex reflection group case? In this paper we begin to answer this
question by establishing results in two directions. First, under conditions
closely analogous to those existing for the real case, we give explicit
relations between coefficients in an element centralizing a generator. Second,
we introduce a tool for dealing with a major challenge of the complex case --
the ``instability'' of certain double cosets -- through the definition and use
of a double coset graph. We use these results to find integral bases for the
centralizers of generators as well as the centres of the Hecke algebras of
types $G_4$ and $G(4,1,2)$.
Keywords: complex reflection group; Hecke algebra; centre; centralizer;
modular; double coset.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 23:57:33 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Francis",
"Andrew",
""
]
] |
0707.2823 | Masayuki Sato | M.Sato, S. Yasui, M. Kimura, T. Hikihara and A.J. Sievers | Management of localized energy in discrete nonlinear transmission lines | submitted | null | 10.1209/0295-5075/80/30002 | null | nlin.PS | null | The manipulation of locked intrinsic localized modes/discrete breathers is
studied experimentally in nonlinear electric transmission line arrays.
Introducing a static lattice impurity in the form of a capacitor, resistor or
inductor has been used both to seed or destroy and attract or repel these
localized excitations. In a nonlinear di-element array counter propagating
short electrical pulses traveling in the acoustic branch are used to generate a
stationary intrinsic localized mode in the optic branch at any particular
lattice site. By changing the pulse polarity the same localized excitation can
be eliminated demonstrating that the dynamical impurity associated with the
propagating electrical pulse in the acoustic branch can trigger optical
localized mode behavior.
| [
{
"version": "v1",
"created": "Wed, 18 Jul 2007 23:59:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sato",
"M.",
""
],
[
"Yasui",
"S.",
""
],
[
"Kimura",
"M.",
""
],
[
"Hikihara",
"T.",
""
],
[
"Sievers",
"A. J.",
""
]
] |
0707.2824 | Mikolaj Korzynski | Mikolaj Korzynski | Quasi--local angular momentum of non--symmetric isolated and dynamical
horizons from the conformal decomposition of the metric | Final version to appear in Classical and Quantum Gravity. One
reference added | Class.Quant.Grav.24:5935-5944,2007 | 10.1088/0264-9381/24/23/015 | null | gr-qc | null | A new definition of quasi--local angular momentum of non--axisymmetric
marginally outer trapped surfaces is proposed. It is based on conformal
decomposition of the two--dimensional metric and the action of the group of
conformal symmetries. The definition is completely general and agrees with the
standard one in axi--symmetric surfaces.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 00:37:40 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 22:55:15 GMT"
},
{
"version": "v3",
"created": "Mon, 1 Oct 2007 22:01:10 GMT"
},
{
"version": "v4",
"created": "Wed, 24 Oct 2007 10:20:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Korzynski",
"Mikolaj",
""
]
] |
0707.2825 | Yongli Ping | Yongli Ping, Lixin Xu, Chengwu Zhang, and Hongya Liu | Dark Energy in Global Brane Universe | 8 pages,4 figures | Int.J.Mod.Phys.D16:1633-1640,2007 | 10.1142/S0218271807011024 | null | gr-qc | null | We discuss the exact solutions of brane universes and the results indicate
the Friedmann equations on the branes are modified with a new density term.
Then, we assume the new term as the density of dark energy. Using Wetterich's
parametrization equation of state (EOS) of dark energy, we obtain the new term
varies with the red-shift z. Finally, the evolutions of the mass density
parameter $\Omega_2$, dark energy density parameter $\Omega_x$ and deceleration
parameter q_2 are studied.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 00:40:13 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 01:29:54 GMT"
},
{
"version": "v3",
"created": "Thu, 20 Dec 2007 12:18:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ping",
"Yongli",
""
],
[
"Xu",
"Lixin",
""
],
[
"Zhang",
"Chengwu",
""
],
[
"Liu",
"Hongya",
""
]
] |
0707.2826 | Yuji Urata | Yuji Urata, Ryo Yamazaki, Takanori Sakamoto, Kuiyun Huang, Weikang
Zheng, Goro Sato, Tsutomu Aoki, Jinsong Deng, Kunihito Ioka, WingHuen Ip,
Koji S. Kawabata, YiHsi Lee, Xin Liping, Hiroyuki Mito, Takashi Miyata,
Yoshikazu Nakada, Takashi Ohsugi, Yulei Qiu, Takao Soyano, Kenichi Tarusawa,
Makoto Tashiro, Makoto Uemura, Jianyan Wei, and Takuya Yamashita | Testing the External Shock Model of Gamma-Ray Bursts using the Late-Time
Simultaneous Optical and X-ray Afterglows | Accepted for publication in ApJL. 12 page, 2 figures, 2 tables | null | 10.1086/522930 | null | astro-ph | null | We study the ``normal'' decay phase of the X-ray afterglows of gamma-ray
bursts (GRBs), which follows the shallow decay phase, using the events
simultaneously observed in the R-band. The classical external shock model -- in
which neither the delayed energy injection nor time-dependency of shock
micro-physics is considered -- shows that the decay indices of the X-ray and
R-band light curves, $\alpha_{\rm X}$ and $\alpha_{\rm O}$, obey a certain
relation, and that in particular, $\alpha_{\rm O}-\alpha_{\rm X}$ should be
larger than -1/4 unless the ambient density increases with the distance from
the central engine. For our selected 14 samples, we have found that 4 events
violate the limit at more than the 3$\sigma$ level, so that a fraction of
events are outliers of the classical external shock model at the ``normal''
decay phase.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 00:50:12 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 12:06:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Urata",
"Yuji",
""
],
[
"Yamazaki",
"Ryo",
""
],
[
"Sakamoto",
"Takanori",
""
],
[
"Huang",
"Kuiyun",
""
],
[
"Zheng",
"Weikang",
""
],
[
"Sato",
"Goro",
""
],
[
"Aoki",
"Tsutomu",
""
],
[
"Deng",
"Jinsong",
""
],
[
"Ioka",
"Kunihito",
""
],
[
"Ip",
"WingHuen",
""
],
[
"Kawabata",
"Koji S.",
""
],
[
"Lee",
"YiHsi",
""
],
[
"Liping",
"Xin",
""
],
[
"Mito",
"Hiroyuki",
""
],
[
"Miyata",
"Takashi",
""
],
[
"Nakada",
"Yoshikazu",
""
],
[
"Ohsugi",
"Takashi",
""
],
[
"Qiu",
"Yulei",
""
],
[
"Soyano",
"Takao",
""
],
[
"Tarusawa",
"Kenichi",
""
],
[
"Tashiro",
"Makoto",
""
],
[
"Uemura",
"Makoto",
""
],
[
"Wei",
"Jianyan",
""
],
[
"Yamashita",
"Takuya",
""
]
] |
0707.2827 | Nadya Gorlova | N. Gorlova (Univ. Florida), Z. Balog, G. H. Rieke, J. Muzerolle, K. Y.
L. Su (Univ. Arizona), V. D. Ivanov (ESO), E. T. Young (Univ. Arizona) | Debris Disks in NGC 2547 | Accepted to ApJ, 29 pages, 13 figs. A Note in Proof concerning
cluster's age was added in the original submission of 2007 July 19. Full
Tables 1 and 2 in the electronic form together with the article with full
resolution figures are available at
http://www.astro.ufl.edu/~ngorlova/disksNGC2547/ | Astrophys.J.670:516-535,2007 | 10.1086/521671 | null | astro-ph | null | We have surveyed the 30 Myr-old cluster NGC 2547 for planetary debris disks
using Spitzer. At 4.5-8 um we are sensitive to the photospheric level down to
mid-M stars (0.2 Msol) and at 24 um to early-G stars (1.2 Msol). We find only
two to four stars with excesses at 8 um out of ~400-500 cluster members,
resulting in an excess fraction <~1 percent at this wavelength. By contrast,
the excess fraction at 24 um is ~40 percent (for B-F types). Out of four
late-type stars with excesses at 8 um two marginal ones are consistent with
asteroid-like debris disks. Among stars with strong 8 um excesses one is
possibly from a transitional disk, while another one can be a result of a
catastrophic collision. Our survey demonstrates that the inner 0.1-1 AU parts
of disks around solar-type stars clear out very thoroughly by 30 Myrs of age.
Comparing with the much slower decay of excesses at 24 and 70 um, disks clear
from the inside out, of order 10 Myr for the inner zones probed at 8 um
compared with a hundred or more Myr for those probed with the two longer
wavelengths.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 01:28:00 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 18:21:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gorlova",
"N.",
"",
"Univ. Florida"
],
[
"Balog",
"Z.",
"",
"Univ. Arizona"
],
[
"Rieke",
"G. H.",
"",
"Univ. Arizona"
],
[
"Muzerolle",
"J.",
"",
"Univ. Arizona"
],
[
"Su",
"K. Y. L.",
"",
"Univ. Arizona"
],
[
"Ivanov",
"V. D.",
"",
"ESO"
],
[
"Young",
"E. T.",
"",
"Univ. Arizona"
]
] |
0707.2828 | Z.K.-H. Chu | Zotin K.-H. Chu | Rapid Transport of Glassy Supersolid Helium in Wavy-Rough Nanpores | one Figure | null | null | null | physics.gen-ph | null | We show that the presumed wavy roughness distributed along the wall of
different nanopores (radius : a around 3.5 nm for Vycor or a silica glass;
around 245 nm for porous gold) will induce larger volume flow rates of solid
helium (of which there is a minimum) which might explain reported experimental
differences of the supersolid fractions observed so far.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 01:58:21 GMT"
}
] | 2007-07-24T00:00:00 | [
[
"Chu",
"Zotin K. -H.",
""
]
] |
0707.2829 | Yongli Ping | Yongli Ping, Lixin Xu, Hongya Liu | Correspondence Between DGP Brane Cosmology and 5D Ricci-flat Cosmology | 8 pages, 1 figure, accepted by MPLA, added reference | Mod.Phys.Lett.A23:695-702,2008 | 10.1142/S0217732308024079 | null | gr-qc | null | We discuss the correspondence between the DGP brane cosmology and 5D
Ricci-flat cosmology by letting their metrics equal each other. By this
correspondence, a specific geometrical property of the arbitrary integral
constant I in DGP metric is given and it is related to the curvature of 5D
bulk. At the same time, the relation of arbitrary functions $\mu$ and $\nu$ in
a class of Ricci-flat solutions is obtained from DGP brane metric.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 02:13:58 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 01:34:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ping",
"Yongli",
""
],
[
"Xu",
"Lixin",
""
],
[
"Liu",
"Hongya",
""
]
] |
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